Liquid composition and ink set, and image-forming process and apparatus using the same

ABSTRACT

Disclosed herein is a colorless or pale-colored liquid composition comprising a cationic substance, wherein the liquid composition contains in combination a cationic substance and a nonionic polymeric substance.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a technique capable of lesseningbleeding which occurs upon the formation of color images with inks andproviding images high in water fastness. In particular, it relates to animage-forming process and an apparatus making good use of an ink-jetsystem, and a liquid composition and an ink set, which are suitable foruse in such process and apparatus.

[0003] 2. Related Background Art

[0004] An ink-jet recording method is a system in which recording isconducted by flying out droplets of an ink to apply them to a recordingmedium such as paper. In particular, according to the methods disclosedin Japanese Patent Publication Nos. 61-59911, 61-59912 and 61-59914, inwhich an electrothermal converter is used as an ejection-energy supplymeans to apply thermal energy to an ink so as to generate bubbles,thereby ejecting droplets of the ink, the formation of a high-densitymulti-orifice in a recording head can be realized with ease, andhigh-resolution and high-quality images can be recorded at high speed.

[0005] However, the conventional inks used in ink-jet recordinggenerally comprise, as a principal component, water, and includeadditionally a water-soluble high boiling solvent such as glycol for thepurpose of preventing drying and clogging, and the like. When such anink has been used to conduct recording on plain paper, there have beenencountered disadvantages that fixing ability cannot be sufficientlyachieved, and image irregularity occurs, which appears to be attributedto the uneven distribution of the filler and size on the surface of therecording paper. In particular, when color images are intended to form,plural inks of different colors are overlapped one after another beforethey are fixed to paper. Therefore, color bleeding and uneven colormixing have occurred at portions of boundaries between images ofdifferent colors (this phenomenon will hereinafter be referred to as“bleeding” simply), resulting in a failure to obtain satisfactoryimages.

[0006] As a means for enhancing fixing ability of inks, Japanese PatentApplication Laid-Open No. 55-65269 discloses the addition of a compoundcapable of enhancing penetrability, such as a surfactant, into the inks.Besides, Japanese Patent Application Laid-Open No. 55-66976 disclosesthe use of inks comprising, as a principal component, a volatilesolvent. However, the former method has involved a disadvantage thatalthough the penetrability of the inks into recording paper is improved,and so the fixing ability is improved and bleeding can be prevented tosome extent, the image density and the saturation of the resulting imageare lowered because coloring materials penetrate deeply into therecording paper together with the inks. In addition, the inks have alsoinvolved a problem that they spread in lateral directions, resulting inreduction of edge sharpness and resolution. On the other hand, thelatter method is liable to cause clogging due to the evaporation of thesolvent in a nozzle of a recording head in addition to theabove-described disadvantages. Such methods have hence not beenpreferred.

[0007] In order to improve the above-described problems, further, therehave been disclosed methods of applying a liquid, which can make thequality of images better, to a recording medium prior to the jetting ofa recording ink.

[0008] For example, Japanese Patent Application Laid-Open No. 63-60783discloses a method in which a liquid containing a basic polymer isapplied to a recording medium, and recording is then conducted with inkscontaining an anionic dye. Japanese Patent Application Laid-Open No.63-22681 discloses a recording method in which the first liquidcontaining a reactive chemical species and the second liquid containinga compound reacting with the reactive chemical species are mixed on arecording medium. Japanese Patent Application Laid-Open No. 63-299971discloses a method in which a liquid containing an organic compoundhaving two or more cationic groups per molecule is applied to arecording medium, and recording is then conducted with inks containingan anionic dye. Japanese Patent Application Laid-Open No. 64-9279discloses a method in which an acidic liquid containing succinic acid orthe like is applied to a recording medium, and recording is thenconducted with inks containing an anionic dye.

[0009] Further, Japanese Patent Application Laid-Open Nos. 64-63185 and64-69381 disclose a method of applying a liquid, which insolubilizesdyes, to a recording medium prior to recording.

[0010] However, all these methods intend to prevent bleeding of imagesor improve the water fastness of images owing to the deposition of thedyes themselves in the inks. Therefore, these methods are stillinsufficient in the effect to prevent the above-described bleedingbetween inks of different colors, and moreover poor in coverability ofthe inks on pulp fibers in the recording paper because the dyesdeposited tend to distribute unevenly on the recording paper, resultingin reduction of evenness of images.

SUMMARY OF THE INVENTION

[0011] With the foregoing circumstances in view, the present inventionhas been completed with a view toward satisfying the following fiverequirements for ink-jet recording on plain paper:

[0012] (1) being able to provide images excellent in quality ofcharacters while retaining good fixing ability;

[0013] (2) being able to achieve sufficient image density and providesolid images high in evenness; and in particular, upon formation ofcolor images on plain papers

[0014] (3) being able to prevent bleeding;

[0015] (4) being excellent in color reproductivity and being able toprovide high-fine images; and

[0016] (5) being able to achieve perfect water fastness of recordedimages.

[0017] The above object can be achieved by the present inventiondescribed below.

[0018] In the first aspect of the present invention, there is provided aliquid composition comprising a cationic substance, wherein the liquidcomposition contains in combination a cationic substance and a nonionicpolymeric substance.

[0019] In the second aspect of the present invention, there is provideda liquid composition comprising a cationic substance, wherein the liquidcomposition contains in combination a cationic oligomer having amolecular weight distribution in which a peak exists in a molecularweight region, and a nonionic polymeric substance.

[0020] In the third aspect of the present invention, there is provided aliquid composition comprising a cationic substance, wherein the cationicsubstance has a molecular weight distribution in which at least one peakexists in two molecular weight regions.

[0021] In the fourth aspect of the present invention, there is providedan ink set comprising in combination one of the above-described liquidcompositions and at least one of yellow, magenta, cyan, black, red, blueand green inks.

[0022] In the fifth aspect of the present invention, there is providedan ink set comprising in combination one of the above-described liquidcompositions and three inks of yellow, magenta and cyan colors.

[0023] In the sixth aspect of the present invention, there is providedan ink set comprising in combination one of the above-described liquidcompositions and four inks of yellow, magenta, cyan and black colors.

[0024] According to the present invention, the above inks may contain ananionic compound, and the anionic compound may be a polymeric substancehaving a molecular weight of at least 5,000, or a surfactant.

[0025] In the seventh aspect of the present invention, there is provideda process of forming an image, which comprises the steps of (A) applyingone of the above-described liquid compositions to at least animage-forming region of a recording medium and (B) applying an inkcomprising an anionic compound to the recording medium by an ink-jetsystem.

[0026] In the eighth aspect of the present invention, there is providedan image forming apparatus comprising one of the above-described inksets and an ink-jet means.

[0027] In the ninth aspect of the present invention, there is providedan image forming apparatus comprising the first recording unit equippedwith a container part containing one of the above-described liquidcompositions and an ejection means therefor, and the second recordingunit equipped with container parts separately containing inks comprisingan anionic compound and ejection means therefor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 is a longitudinal cross-sectional view of a head of anink-jet recording apparatus.

[0029]FIG. 2 is a transverse cross-sectional view of the head of theink-jet recording apparatus.

[0030]FIG. 3 is a perspective view of the appearance of another head ofthe ink-jet recording apparatus.

[0031]FIG. 4 is a perspective view of an illustrative ink-jet recordingapparatus.

[0032]FIG. 5 is a longitudinal cross-sectional view of an ink cartridge.

[0033]FIG. 6 is a perspective view of a recording unit.

[0034]FIG. 7 is a perspective view illustrating a recording part used inexamples of the present invention, in which a plurality of recordingheads is arranged.

[0035]FIG. 8 is a perspective view of another recording head used in thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] The operation of the present invention will hereinafter bedescribed.

[0037] In the present invention, the liquid composition and an ink or apigment ink are mixed on recording paper or at a position penetrated inthe recording paper. As a result, as the first step of the reaction, thelow-molecular weight cationic substance or cationic oligomer containedin the liquid composition associates with a water-soluble dye having ananionic group used in the ink or an anionic compound used in the pigmentink owing to ionic interaction, so that they momentarily separate fromthe respective solution phases. As a result, breaking of dispersionoccurs in the pigment ink, whereby aggregates of the pigment are formed.

[0038] As the second step of the reaction, the aggregates formed by theassociation of the dye and the low-molecular weight cationic substanceor cationic oligomer, or the aggregates of the pigment are adsorbed onthe nonionic or cationic polymeric substances. Therefore, the aggregatesof the dye formed by the association in the dye ink, or the aggregatesof the pigment further increase in size, and become difficult to enterthe interfiber spaces of the recording paper. As a result, only theliquid component separated from the solid component is caused topenetrate into the recording paper, whereby the compatibility of printquality and fixing ability can be achieved. At the same time, theaggregates formed from the low-molecular weight cationic substance orcationic oligomer, the anionic dye in the ink or the anionic compoundand pigment in the pigment ink, and the nonionic or cationic polymericsubstances increase in viscosity and hence do not move with the movementof the liquid medium. In this case, the preferable molecular weights ofthe polymers are at least 2,000 for the nonionic polymers, and at least1,500 for the cationic polymers. Accordingly, the coloring ability ofthe dye or pigment is improved, and inks of different colors are notmixed with each other even if adjoining dots are formed by these inks,for example, upon formation of a full-color image, and so bleeding doesalso not occur. Since the aggregates are insoluble in water inthemselves, the image formed comes to have perfect water fastness. Whenthe pigment is used as a coloring material, the pigment aggregates onthe surface of the recording paper, and so the coverability of theresulting ink is increased, resulting in marked improvement of coloringability.

[0039] The preferred embodiments of the present invention will then bedescribed to explain the present invention in more detail.

[0040] First of all, the liquid composition according to the firstaspect of the present invention will be described.

[0041] The essential components to be contained in the colorless orpale-colored liquid composition described in the first aspect of thepresent invention are as follows:

[0042] (1) a low-molecular weight cationic substance having a molecularweight of at most 1,000, and

[0043] (2) a nonionic polymeric substance having a molecular weight ofat least 2,000.

[0044] On the other hand, the inks used in the present inventioncomprise:

[0045] (3) a water-soluble dye having at least an anionic group,

[0046] while other inks used in the present invention comprise:

[0047] (4) a pigment and an anionic compound.

[0048] The action and effect of the above-described substances are asdescribed above. More specifically, the low-molecular weight cationicsubstance of the component (1) having a molecular weight of at most1,000 (preferably, 100 to 700) associates with the water-soluble dye ofthe component (3) having at least an anionic group, which is containedin the ink, or the anionic compound of the component (4) in the pigmentink owing to ionic interaction to form aggregates. The rate of thisaggregate-forming reaction must be extremely fast.

[0049] Preferable specific examples of the low-molecular weight cationicsubstance of the component (1) having a molecular weight of at most1,000, preferably from 100 to 700, are mentioned below.

[0050] As the preferable examples thereof, may be mentioned compounds ofthe primary, secondary and tertiary amine salt types, specifically, thehydrochlorides, acetates and the like of laurylamine, coconut amine,stearylamine, rosin amine and the like, and besides compounds of thequaternary ammonium salt type, specifically, lauryltrimethylammoniumchloride, lauryldimethylbenzylammonium chloride, benzyltributylammoniumchloride, benzalkonium chloride, cetyltrimethylammonium chloride and thelike, pyridinium salt type compounds, specifically, cetylpyridiniumchloride, cetylpyridinium bromide and the like, imidazoline typecationic compounds, specifically, 2-heptadecenylhydroxyethylimidazolineand the like, and ethylene oxide adducts of secondary alkylamines,specifically, dihydroxyethylstearylamine and the like.

[0051] In the first aspect of the present invention, amphotericsurfactants exhibiting cationic properties in a certain pH region mayalso be used.

[0052] More specifically, there are mentioned amino acid type amphotericsurfactants, compounds of the RNHCH₂—CH₂COOH type, betaine typecompounds, specifically, stearyldimethylbetaine andlauryldihydroxyethylbetaine, and the like. If these amphotericsurfactants are used, it goes without saying that the colorless orpale-colored liquid composition must be adjusted either so as to have apH not higher than their isoelectric point or so as to reach the pH nothigher than the isoelectric point when mixed with the ink on a recordingmedium.

[0053] Although the examples of the low-molecular weight cationiccompounds have been mentioned above, it goes without saying thatcationic compounds usable in the first aspect of the present inventionare not always limited to these compounds.

[0054] The action and effect of the nonionic polymeric substance of thecomponent (2) having a molecular weight of at least 2,000 in the firstaspect of the present invention are as described above. Morespecifically, as the second step of the reaction of the liquidcomposition with the ink, the aggregates of the above-described dye orthe anionic compound in the pigment ink and the low-molecular weightcationic substance formed by the association are adsorbed into itsmolecule to increase the size of the aggregates of the dye or thepigment formed by the association so as to become difficult to enter theinterfiber spaces of the recording paper, whereby only the liquidcomponent separated from the solid component is caused to penetrate intothe recording paper to achieve the compatibility of print quality andfixing ability.

[0055] As specific examples of the component (2), may be mentionednonionic water-soluble polymers, i.e., polyacrylamide, polyvinylpyrrolidone, water-soluble cellulosics such as carboxymethylcellulose,hydroxymethylcellulose and hydroxypropylcellulose, polyvinyl methylether, polyvinyl acetal, and polyvinyl alcohol. It goes without sayingthat the component (2) is limited to these polymeric substances. Theeffect of these polymeric substances in the practice of the presentinvention can be sufficiently achieved so far as they have a molecularweight of at least 2,000. However, polymeric substances having amolecular weight of not lower than 2,000 but not higher than 10,000 aremore preferred.

[0056] The molecular weight of the polymeric substance in the presentinvention means a weight average molecular weight determined in terms ofpolyethylene oxide by means of GPC (gel permeation chromatography)unless expressly noted.

[0057] The amount of these components to be contained in the colorlessor pale-colored liquid composition may preferably be within a range offrom 0.05 to 20% by weight, more preferably from 0.5 to 5% by weightbased on the total weight of the liquid composition. It is howevernecessary to determine an optimum range according to the combination ofthe individual substances to be used. The mixing ratio of thelow-molecular weight cationic substance of the component (1) to thepolymeric substance of the component (2) in the liquid composition iswithin a range of from 10:1 to 1:10, preferably from 5:1 to 1:5 byweight. If this ratio exceeds 10:1, the water fastness of the resultingprint tends to be deteriorated. On the other hand, if the ratio is notlower than 1:10, the prevention of bleeding becomes insufficient, and sothe edge sharpness of images formed tends to be reduced.

[0058] Second, the liquid composition according to the second aspect ofthe present invention is a liquid composition comprising a cationicsubstance and characterized in that the composition comprises incombination a cationic oligomer having a molecular weight distributionin which a peak exists in a molecular weight region of not higher than1,000, and a nonionic polymeric substance having a molecular weight ofat least 2,000. The liquid composition may preferably further contain acationic surfactant.

[0059] The action and effect of the liquid composition according to thesecond aspect of the present invention are as described above. Morespecifically, the cationic oligomer contained in the liquid composition,which has a molecular weight distribution in which a peak exists in amolecular weight region of not higher than 1,000, first associates withthe anionic compound contained in the ink owing to ionic interaction toform aggregates. The rate of this aggregate-forming reaction must beextremely fast.

[0060] The components of the liquid composition according to the secondaspect of the present invention will hereinafter be described. Asspecific examples of monomer units forming the cationic oligomer havinga molecular weight distribution in which a peak exists in a molecularweight region of not higher than 1,000, said oligomer being an essentialcomponent to the liquid composition according to the second aspect ofthe present invention, may be mentioned vinylamine, allylamine,vinylpyridine, vinylimidazole, N,N-dimethylaminoacrylamide,ethyleneimine and 2-oxazoline. However, the monomer units are notlimited to these compounds.

[0061] Examples of cationic oligomers formed from the monomer unitsmentioned above include polycations such as polyvinylamine,polyallylamine, polyvinylpyridine and polyethyleneimine and thehydrochlorides, acetates and sulfates thereof, and besides thequaternary ammonium salts of polyoxyethylene derivatives, which have thestructure

[0062] wherein R and R′ denote individually an alkyl or benzyl, m+n isan integer of 2 to 10, X⁻ denotes Br⁻, Cl⁻, I⁻, CH₃COO⁻, C₂H₅SO₃ ⁻ orthe like. However, the oligomers are not limited to these oligomers.

[0063] The oligomers usable in the second aspect of the presentinvention may be copolymers with monomer units having a nonionic pendantgroup.

[0064] With respect to the molecular weight distribution of the cationicoligomers used in the second aspect of the present invention, theindividual oligomers may be subjected to GPC measurement in advance.Alternatively, the molecular weight distribution may be determined inthe following manner. Namely, after the molecular weight distribution ofthe liquid composition itself is determined, a sufficient amount of theink containing the dye having at least an anionic group is mixed understirring with the liquid composition in a beaker, and precipitate formedis removed. Thereafter, the GPC measurement is conducted again tocompare the measurement results before the mixing of the ink and afterthe mixing of the ink and the removal of the precipitate with eachother, whereby the molecular weight distribution of the oligomer isfound from the molecular weight distribution of the componentprecipitated by the dye in the ink and removed from the system.

[0065] In order to more enhance the effect of the present invention,such a cationic surfactant as mentioned below may be further containedin the liquid composition.

[0066] Specific examples of such a cationic surfactant include compoundsof the primary, secondary and tertiary amine salt types, specifically,the hydrochlorides, acetates and the like of laurylamine, coconut amine,stearylamine, rosin amine and the like; compounds of the quaternaryammonium salt type, specifically, lauryltrimethylammonium chloride,lauryldimethylbenzylammonium chloride, benzyltributylammonium chloride,benzalkonium chloride and the like; pyridinium salt type compounds,specifically, cetylpyridinium chloride, cetylpyridinium bromide and thelike; imidazoline type cationic compounds, specifically,2-heptadecenyl-hydroxyethylimidazoline and the like; and ethylene oxideadducts of higher alkylamines, specifically, dihydroxyethylstearylamineand the like.

[0067] In the second aspect of the present invention, amphotericsurfactants exhibiting cationic properties in a certain pH region mayalso be used. More specifically, there are mentioned carboxylic acidtype amphoteric surfactants, such as amino acid type amphotericsurfactants; compounds of the R—NH—CH₂—CH₂—COOH type; and betaine typecompounds, specifically, stearyldimethylbetaine andlauryldihydroxyethylbetaine, and besides amphoteric surfactants of thesulfuric ester type, sulfonic acid type, phosphoric ester type and thelike. If these amphoteric surfactants are used, it goes without sayingthat the liquid composition must be adjusted either so as to have a pHnot higher than their isoelectric point or so as to reach the pH nothigher than the isoelectric point when mixed with the ink on a recordingmedium.

[0068] Although the examples of the cationic compounds have beenmentioned above, it goes without saying that compounds usable in thesecond aspect of the present invention are not always limited to thesecompounds.

[0069] The nonionic polymeric substance having a molecular weight of atleast 2,000, which is another essential component to the liquidcomposition according to the second aspect of the present invention,will hereinafter be described. The action and effect of the nonionicpolymeric substance in the present invention are also as describedabove. More specifically, as the second step of the reaction of theliquid composition with the ink, the aggregates of the dye having theanionic group and the cationic oligomer formed by the association as thefirst step are adsorbed into its molecule to increase the size of theaggregates of the dye formed by the association so as to becomedifficult to enter the interfiber spaces of the recording paper, wherebythe coloring material in the ink is left on the recording paper, andonly the liquid component separated from the solid component is causedto penetrate into the recording paper to achieve the compatibility ofprint quality and fixing ability.

[0070] As specific examples of the nonionic polymeric substanceexhibiting the action and effect as described above, may be mentionednonionic water-soluble polymers, i.e., polyacrylamide, polyvinylpyrrolidone, water-soluble cellulosics such as carboxymethylcellulose,hydroxymethylcellulose and hydroxypropylcellulose, polyvinyl methylether, polyvinyl acetal, and polyvinyl alcohol. It goes without sayingthat the polymeric substance is not limited to these polymericsubstances. The effect of these polymeric substances in the practice ofthe present invention can be sufficiently exhibited so far as they havea molecular weight of at least 2,000. However, polymeric substanceshaving a molecular weight of not lower than 2,000 but not higher than10,000 may preferably be used.

[0071] In order to more enhance the effect of the present invention, acationic polymeric substance may be used in combination with thenonionic polymeric substance described above in the second aspect of thepresent invention. As examples of the cationic polymeric substance usedin this case, may be mentioned polyallylamine hydrochloride, polyaminesulfone hydrochloride, polyvinylamine hydrochloride and chitosanacetate. It goes without saying that the cationic polymeric substance isnot limited to these substances.

[0072] In the second aspect of the present invention, a compoundobtained by partly cationizing a nonionic polymeric substance may beused as the cationic polymeric substance. As specific examples of such acompound, may be mentioned copolymers of vinylpyrrolidone and anaminoalkylalkylate quaternary salt and copolymers of acrylamide and anaminomethylacrylamide quaternary salt. It goes without saying that thecompound is not limited to these compounds.

[0073] If the above-described polymeric substances and the cationicpolymeric substance are soluble in water, there is nothing to be saidagainst them. However, they may be in the form of a dispersion such aslatex or emulsion.

[0074] The amount of these components to be contained in the liquidcomposition according to the second aspect of the present invention maypreferably be within a range of from 0.05 to 20% by weight, morepreferably from 0.5 to 5% by weight based on the total weight of theliquid composition. It is however necessary to determine an optimumrange according to the combination of the individual substances to beused. The mixing ratio of the cationic oligomer to the nonionicpolymeric substance in the liquid composition as described above iswithin a range of from 10:1 to 1:10, preferably from 5:1 to 1:5 byweight. If this ratio exceeds 10:1, the water fastness of the resultingprint tends to be deteriorated. On the other hand, if the ratio is notlower than 1:10, the prevention of bleeding becomes insufficient, and sothe edge sharpness of images formed tends to be reduced. It is hence notpreferable to use these substances outside the above range of the mixingratio.

[0075] The liquid composition according to the third aspect of thepresent invention will hereinafter be described.

[0076] The essential components to be contained in such a liquidcomposition are as follows:

[0077] (21) a low-molecular weight cationic substance having a molecularweight distribution in which at least one peak exists in a molecularweight region of not higher than 1,000, and

[0078] (22) a cationic polymeric substance having a molecular weightdistribution in which at least one peak exists in a molecular weightregion of not lower than 1,500.

[0079] On the other hand, the inks used in the present inventioncomprise:

[0080] (23) a water-soluble dye having at least an anionic group,

[0081] while other inks used in the present invention comprise:

[0082] (24) a pigment and an anionic compound.

[0083] The action and effect of the above-described substances in thethird aspect of the present invention are as described above. Morespecifically, the low-molecular weight cationic substance of thecomponent (21) in which the peak of the molecular weight distributionexists in a region of 1,000 or lower associates with the water-solubledye of the component (23) having at least an anionic group, which iscontained in the ink, or the anionic compound in the pigment ink owingto ionic interaction to form aggregates. The rate of thisaggregate-forming reaction must be extremely fast.

[0084] Preferable specific examples of the low-molecular weight cationicsubstance of the component (21) in which the peak of the molecularweight distribution exists in a region of 1,000 or lower are mentionedbelow. Incidentally, a compound close to monodisperse in the molecularweight distribution may often be used as the low-molecular weightcationic substance in the third aspect of the present invention. Withrespect to a compound having no molecular weight distribution, a usualmolecular weight found from its chemical formula is considered as aposition of the peak.

[0085] As preferable examples thereof, may be mentioned compounds of theprimary, secondary and tertiary amine salt types, specifically, thehydrochlorides, the acetates and the like of laurylamine, coconut amine,stearylamine, rosin amine and the like, and besides compounds of thequaternary ammonium salt type, specifically, lauryltrimethylammoniumchloride, lauryldimethylbenzylammonium chloride, benzyltributylammoniumchloride, benzalkonium chloride, cetyltrimethylammonium chloride and thelike, pyridinium salt type compounds, specifically, cetylpyridiniumchloride, cetylpyridinium bromide and the like, imidazoline typecationic compounds, specifically, 2-heptadecenylhydroxyethylimidazolineand the like, and ethylene oxide adducts of secondary alkylamines,specifically, dihydroxyethylstearylamine and the like.

[0086] In the third aspect of the present invention, amphotericsurfactants exhibiting cationic properties in a certain pH region mayalso be used.

[0087] More specifically, there are mentioned amino acid type amphotericsurfactants, compounds of the RNHCH₂—CH₂COOH type, betaine typecompounds, specifically, stearyldimethylbetaine andlauryldihydroxyethylbetaine, and the like. If these amphotericsurfactants are used, it goes without saying that the colorless orpale-colored liquid composition must be adjusted either so as to have apH not higher than their isoelectric point or so as to reach the pH nothigher than the isoelectric point when mixed with the ink on a recordingmedium.

[0088] Although the examples of the low-molecular weight cationiccompounds have been mentioned above, it goes without saying thatcompounds usable in the third aspect of the present invention are notalways limited to these compounds.

[0089] The action and effect of the cationic polymeric substance of thecomponent (22) in which the peak of the molecular weight distributionexists in a region of not lower than 1,500 are as described above. Morespecifically, as the second step of the reaction of the liquidcomposition with the ink, the aggregates of the above-described dye orthe anionic compound in the pigment ink and the low-molecular weightcationic substance formed by the association are adsorbed into itsmolecule to increase the size of the aggregates of the dye or thepigment formed by the association so as to become difficult to enter theinterfiber spaces of the recording paper, whereby only the liquidcomponent separated from the solid component is caused to penetrate intothe recording paper to achieve the compatibility of print quality andfixing ability.

[0090] As specific examples of the cationic polymeric substance of thecomponent (22), may be mentioned polyallylamine, polyamine sulfone,polyvinylamine, chitosan, and neutralized products or partly neutralizedproducts of these compounds with an acid such as hydrochloric acid oracetic acid. It goes without saying that the cationic polymericsubstance is not limited to these substances. The effect of thesepolymeric substances in the practice of the present invention can besufficiently exhibited so far as they have a molecular weightdistribution in which at least one peak exists in a molecular weightregion of not lower than 1,500. However, polymeric substances having amolecular weight of not lower than 1,500 but not higher than 10,000 maybe preferably used.

[0091] As other examples of the cationic polymeric substance of thecomponent (22) used, may be mentioned compounds obtained by partlycationizing a nonionic polymeric substance.

[0092] As specific examples of such compounds, may be mentionedcopolymers of vinylpyrrolidone and an aminoalkylalkylate quaternary saltand copolymers of acrylamide and an aminomethylacrylamide quaternarysalt. It goes without saying that the compound is not limited to thesecompounds.

[0093] If the above-described cationic polymeric substances are solublein water, there is nothing to be said against them. However, they may bein the form of a dispersion such as latex or emulsion.

[0094] The amount of these components to be contained in the colorlessor pale-colored liquid composition may preferably be within a range offrom 0.05 to 20% by weight, more preferably from 0.5 to 5% by weightbased on the total weight of the liquid composition. It is howevernecessary to determine an optimum range according to the combination ofthe individual substances to be used. The mixing ratio of thelow-molecular cationic substance of the component (21) to the polymericsubstance of the component (22) in the liquid composition is within arange of from 10:1 to 1:10, preferably from 5:1 to 1:5 by weight. Ifthis ratio exceeds 10:1, the water fastness of the resulting print tendsto be deteriorated. On the other hand, if the ratio is not lower than1:10, the prevention of bleeding becomes insufficient, and so the edgesharpness of images formed tends to be reduced.

[0095] In the present invention, the use of the cationic polymericsubstance has more effects than the use of the nonionic polymericsubstance from the viewpoint of the coloring ability of dyes andpigments, the resistance to bleeding in a region in which a shot-in inkquality is great, and water fastness under severe conditions.

[0096] Other components making up the colorless or pale-colored liquidcompositions described above will then be described specifically.

[0097] The colorless or pale-colored liquid compositions are generallycomposed of water, a water-soluble organic solvent and other additivesin addition to the above-described respective components. As examples ofthe water-soluble organic solvent used include amides such asdimethylformamide and dimethylacetoamide, ketones such as acetone,ethers such as tetrahydrofuran and dioxane, polyalkylene glycols such aspolyethylene glycol and polypropylene glycol, alkylene glycols such asethylene glycol, propylene glycol, butylene glycol, triethylene glycol,thiodiglycol, hexylene glycol and diethylene glycol; 1,2,6-hexanetriol,lower alkyl ethers of polyhydric alcohols, such as ethylene glycolmethyl ether, diethylene glycol monomethyl ether and triethylene glycolmonomethyl ether, monohydric alcohols such as ethanol, isopropylalcohol, n-butyl alcohol and isobutyl alcohol, and besides, glycerol,N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, triethanolamine,sulfolane and dimethyl sulfoxide.

[0098] No particular limitation is imposed on the content of thewater-soluble organic solvent. However, it may preferably be within arange of from 5 to 60% by weight, more preferably from 5 to 40% byweight based on the total weight of the liquid composition.

[0099] Besides the above components, additives such as a viscositymodifier, pH adjustor, antiseptic, surfactant, antioxidant andevaporation accelerator may be incorporated as needed. The selection ofthe surfactant is particularly important from the viewpoint ofcontrolling the penetrability of the liquid composition.

[0100] The colorless or pale-colored liquid composition means acomposition having a color tone which does not change the color tone ofthe recording inks. With respect to preferable physical property rangesat about 25° C. of the colorless or pale-colored liquid compositions,the pH may be within a range of from 3 to 12, preferably from 3 to 8,more preferably from 3 to 5, the surface tension may be within a rangeof from 10 to 60 dyne/cm, preferably 10 to 40 dyne/cm, and the viscositymay be within a range of from 1 to 30 cP.

[0101] Inks described in the present invention are commonly usedconcurrently with the liquid composition in the first to third aspectsmentioned above.

[0102] Then, the recording inks (type I) useful in the practice of thepresent invention according to an aspect of the present invention willhereinafter be described.

[0103] Besides a water-soluble dye having the anionic group describedabove, the recording inks (type I) used in the present inventioncomprise water and a water-soluble organic solvent, and optionally othercomponents such as a viscosity modifier, pH adjustor, antiseptic,surfactant and antioxidant.

[0104] No particular limitation is imposed on the dyes having theanionic group used in the present invention so far as they arewater-soluble acid dyes, direct dyes or reactive dyes, which aredescribed in COLOR INDEX. Any dye not described in COLOR INDEX may alsobe used without any particular limitation so far as it has an anionicgroup, for example, a sulfonic group or a carboxylic group. Among thewater-soluble dyes used herein, those having dependence of solubility onpH are also included as a matter of course.

[0105] As the water-soluble organic solvent used in the inks, thewater-soluble organic solvents used in the colorless or pale-coloredliquid compositions as described above may be used similarly. The sameshall apply to the preferable range of the content of the water-solubleorganic solvent. The preferable physical property ranges are exactly thesame as those of the colorless or pale-colored liquid compositions.

[0106] In order to more enhance the effects of the present invention, ananionic surfactant or an anionic polymeric substance may be added to theinks in addition to the components described above. Alternatively, theabove-described amphoteric surfactant may also be used after adjustingit to a pH not lower than its isoelectric point. As examples of theanionic surfactant used, may be mentioned those commonly used in inks,such as carboxylic acid salt type, sulfuric acid ester type and sulfonicacid salt type. As examples of the anionic polymeric substance, may bementioned alkali-soluble resins, specifically, sodium polyacrylate andcopolymers obtained by introducing an acrylic acid in a part of apolymer. It goes without saying that such compounds are not limited tothese compounds.

[0107] Then, the recording inks (type II) useful in the practice of thepresent invention according to another aspect of the present inventionwill hereinafter be described.

[0108] Besides a pigment and an anionic compound, the recording inks(type II) comprise water and a water-soluble organic solvent, andoptionally other components such as a viscosity modifier, pH adjustor,antiseptic, surfactant and antioxidant. In this aspect, the anioniccompound may be a dispersant for the pigment, or if the dispersant forthe pigment is not an anionic compound, an anionic compound may be usedin addition to the dispersant. It goes without saying that even if thedispersant is an anionic compound, another anionic compound may beadded.

[0109] No particular limitation is imposed on the pigments used in thisaspect of the present invention. Specifically, the following pigmentsmay preferably be used.

[0110] First of all, as carbon black used in a black pigment ink, theremay be used those produced in accordance with the furnace process orchannel process and having a primary particle size of 15 to 40 nm, aspecific surface area of 50 to 300 m²/g as determined in accordance withthe BET method, an oil absorption of 40 to 150 ml/100 g as determined byusing DBP, a volatile matter of 0.5 to 10%, and a pH of 2 to 9, forexample, commercially-available carbon black such as No. 2300, No. 900,MCF 88, No. 40, No. 52, MA 7, MA 8 and No. 2200 B (all, products ofMitsubishi Chemical Industries Limited), RAVEN 1255 (product ofColumbian Carbon Japan Limited), REGAL 400R, REGAL 660R and MOGUL L(all, products of Cabot Company), and Color Black FW1, Color Black FW18,Color Black S170, Color Black S150, Printex 35 and Printex U (all,products of Degussa). Those newly prepared for the practice of thepresent invention may also be used. As examples of pigments used inyellow, magenta and cyan inks, may be mentioned C.I. Pigment Yellow 1,C.I. Pigment Yellow 2, C.I. Pigment Yellow 3, C.I. Pigment Yellow 13,C.I. Pigment Yellow 16 and C.I. Pigment Yellow 83; C.I. Pigment Red 5,C.I. Pigment Red 7, C.I. Pigment Red 12, C.I. Pigment Red 48 (Ca), C.I.Pigment Red 48 (Mn), C.I. Pigment Red 57 (Ca), C.I. Pigment Red 112 andC.I. Pigment Red 122; and C.I. Pigment Blue 1, C.I. Pigment Blue 2, C.I.Pigment Blue 3, C.I. Pigment Blue 15:3, C.I. Pigment Blue 16, C.I.Pigment Blue 22, C.I. Vat Blue 4 and C.I. Vat Blue 6, respectively.However, those newly prepared for the practice of the present inventionmay also be used. The pigments as mentioned above may preferably be usedwithin a range of from 1 to 20% by weight, more preferably from 2 to 12%by weight based on the total weight of their corresponding inks.

[0111] As the dispersant used in this aspect of the present invention,any resin may be used so far as it is soluble in water. However, theresin preferably has a weight average molecular weight ranging from1,000 to 30,000, more preferably from 3,000 to 15,000. Specific examplesthereof include block copolymers, graft copolymers and random copolymerscomposed of at least two monomers (at least one monomer beinghydrophilic) selected from hydrophobic monomers such as styrene, styrenederivatives, vinylnaphthalene, vinylnaphthalene derivatives andaliphatic alcohol esters of α,β-ethylenically unsaturated carboxylicacids, acrylic acid, acrylic acid derivatives, maleic acid, maleic acidderivatives, itaconic acid, itaconic acid derivatives, fumaric acid, andfumaric acid derivatives, and salts of these copolymers. These resinsare alkali-soluble resins which dissolve in an aqueous solution of abase. Besides, homopolymers composed of a hydrophilic monomer or saltsthereof may be used. Further, other water-soluble resins such aspolyvinyl alcohol, carboxymethylcellulose and condensation products ofnaphthalene sulfonic acid and formaldehyde may also be used. However,the use of the alkali-soluble resin has an advantage in that theviscosity of the resultant dispersion can be made low, and moreover thepigment can be easily dispersed. The water-soluble resin may preferablybe used in a range of from 0.1 to 5% by weight based on the total weightof the ink.

[0112] It is further desirable that the inks according to this aspect ofthe present invention is adjusted to neutrality or alkalinity,preferably, as the whole because the solubility of the water-solubleresin is enhanced, so that an ink far excellent in long-term storabilitycan be provided. It is more desirable that the pH be adjusted to a rangeof from 7 to 10.

[0113] Examples of the pH adjustor include various kinds of organicamines such as diethanolamine and triethanolamine, inorganic alkalissuch as the hydroxides of alkali metals, for example, sodium hydroxide,lithium hydroxide, potassium hydroxide, etc., organic acids, and mineralacids.

[0114] The pigment and water-soluble resin as described above aredispersed or dissolved in an aqueous medium.

[0115] An aqueous medium suitable for use in the inks (type II)according to this aspect of the present invention is a mixed solvent ofwater and a water-soluble organic solvent. As the water, it ispreferable to use ion-exchanged water (deionized water) instead of tapwater containing various ions.

[0116] As examples of the water-soluble organic solvent used incombination with water, may be mentioned alkyl alcohols having 1 to 4carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol,isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol and tert-butylalcohol; amides such as dimethylformamide and dimethylacetamide; ketonesand ketone alcohols such as acetone and diacetone alcohol; ethers suchas tetrahydrofuran and dioxane; polyalkylene glycols such aspolyethylene glycol and polypropylene glycol; alkylene glycols thealkylene moiety of which has 2 to 6 carbon atoms, such as ethyleneglycol, propylene glycol, butylene glycol, triethylene glycol,thiodiglycol, hexylene glycol and diethylene glycol; 1,2,6-hexanetriol;glycerol; lower alkyl ethers of polyhydric alcohols, such as ethyleneglycol monomethyl (or monoethyl) ether, diethylene glycol methyl (orethyl) ether and triethylene glycol monomethyl (or monoethyl) ether;N-methyl-2-pyrrolidone; 2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone;and the like. Among a number of these water-soluble organic solvents,polyhydric alcohols such as diethylene glycol and lower alkyl ethers ofpolyhydric alcohols, such as triethylene glycol monomethyl (ormonoethyl) ether are preferred.

[0117] In order to achieve good ejection stability, it is effective toadd further ethanol or isopropyl alcohol in an amount of 1% or morebecause the addition of these solvents is considered to permit morestable bubbling of the recording ink on a thin film resistor. However,the addition of these solvents in excess involves a drawback that theprint quality of the resulting print is impaired. The suitableconcentration of these solvents has been found to be 3 to 10% by weight.These solvent have a further effect that the addition of the solvents tothe dispersion prevents foaming upon the preparation of the dispersion,thereby effectively conducting the dispersion.

[0118] The content of the water-soluble organic solvent in the inkaccording to this aspect of the present invention is generally within arange of from 3 to 50%, preferably from 3 to 40% by weight based on thetotal weight of the ink, while the content of water used is within arange of from 10 to 90% by weight, preferably from 30 to 80% by weightbased on the total weight of the ink.

[0119] If the dispersant is not an anionic polymer, an anionic compoundmust be further added to the pigment-containing ink. As anioniccompounds suitably used in this aspect of the present invention, may bementioned polymeric substances such as the alkali-soluble resinsdescribed as the dispersants for the pigments, and besides low-molecularweight anionic surfactants.

[0120] As specific examples of the low-molecular weight anionicsurfactants, may be mentioned disodium lauryl sulfosuccinate, disodiumpolyoxyethylene lauroylethanolamide sulfosuccinate, disodiumpolyoxyethylene alkylsulfosuccinate, carboxylated polyoxyethylene laurylether sodium salt, carboxylated polyoxyethylene tridecyl ether sodiumsalt, sodium polyoxyethylene lauryl ether sulfate, triethanolaminepolyoxyethylene lauryl ether sulfate, sodium polyoxyethylene alkyl ethersulfate, sodium alkylsulfate and triethanolamine alkylsulfate, to which,however, are not limited.

[0121] The suitable amount of the above-described anionic substances tobe used is within a range of from 0.05 to 10% by weight, more preferablyfrom 0.05 to 5% by weight based in the total weight of the ink.

[0122] Further, the inks according to this aspect of the presentinvention may contain, in addition to the above components, asurfactant, antifoaming agent, antiseptic and the like as needed toprovide them as inks having desired physical properties.Commercially-available water-soluble dyes and/or the like may also beadded thereto.

[0123] Examples of the surfactant include anionic surfactants such asfatty acid salts, salts of higher alcohol sulfates, salts of liquidfatty oil sulfates and alkylallylsulfonates; and nonionic surfactantssuch as polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters,polyoxyethylene sorbitan alkyl esters, acetylene alcohol and acetyleneglycol. These surfactants may be suitably chosen for either single useor combined use. The amount of the surfactants to be used may varyaccording to the kind of the dispersant used. However, it may desirablybe within a range of from 0.01 to 5% by weight based on the total weightof the ink. In this case, it is preferred that the amount of thesurfactants added be determined in such a manner that the surfacetension of the resulting ink is 30 dyne/cm or higher. If the surfacetension is lower than this value, such an ink brings about undesirablesituations such as slippage upon printing (defective ink-droplet impact)due to the wetting on orifices in such a recording system as used in thepresent invention.

[0124] Each of the inks (type II) according to this aspect of thepresent invention is prepared in the following manner. The pigment isfirst added to an aqueous solution containing at least the dispersantresin and water, and the mixture is stirred. A dispersion treatment isthen conducted in accordance with a dispersing technique describedbelow, and if necessary, a centrifugation is carried out to obtain adesired dispersion. The components as mentioned above are then added tothe dispersion. The resultant mixture is stirred to prepare the intendedink.

[0125] If the alkali-soluble resin is used, it is necessary to add abase for dissolving the resin in the dispersion. It is also necessary toadd the amine or base required to dissolve the resin in an amount atleast once of the amount of the amine or base calculated out from theacid value of the resin. This calculated amount of the amine or base isfound in accordance with the equation${{Amount}\quad {of}\quad {amine}\quad {or}\quad {base}\quad (g)} = {\frac{{\begin{matrix}{{Acid}\quad {value}} \\{{of}\quad {resin}}\end{matrix} \times \begin{matrix}{Molecular} \\{{weight}\quad {of}\quad {amine}}\end{matrix} \times \begin{matrix}{{Amount}\quad {of}} \\{{resin}\quad (g)}\end{matrix}}\quad}{5600}.}$

[0126] It is further preferable from the view point of improving thedispersion efficiency to conduct premixing for at least 30 minutes priorto the dispersion treatment of the aqueous solution containing thepigment. This premixing serves to improve the wettability of the surfaceof the pigment and facilitate adsorption of the dispersant on thepigment surface.

[0127] In case the alkali-soluble resin is used, preferable examples ofthe bases added to the dispersion include organic amines such asmonoethanolamine, diethanolamine, triethanolamine andaminomethylpropanol, ammonia, and inorganic bases such as potassiumhydroxide and sodium hydroxide.

[0128] Any dispersing machine routinely used may be employed as adispersing machine used in the present invention. As examples thereof,may be mentioned ball mills and sand mills.

[0129] Of these mills, high-speed sand mills are preferred. Examplesthereof include Super Mill, Sand Grinder, Beads Mill, Agitator Mill,Grain Mill, Dyno Mill, Pearl Mill, Coball Mill (all, trade names), etc.

[0130] No particular limitation is imposed on the recording medium usedin the practice of the present invention, and the so-called plain papersuch as paper for copying and bond paper, which are routinely used, arepreferably used. It goes without saying that coated paper speciallyprepared for ink-jet recording, and transparent films for OHP may alsobe suitably used, and besides general-purpose woodfree paper and glossypaper may also be suitably used.

[0131] Any method may be used as the image-forming method according tothe present invention so far as it is a method in which the colorless orpale-colored liquid composition and the ink can be caused to coexist ona recording medium. No problem arises if either of the liquidcomposition and the ink is first applied to the recording medium.

[0132] The term “image-forming region” as used herein means a region ofa recording medium, to which dots of the ink are applied, while the term“the vicinity of the image-forming region” means an outside region about1 to 5 dots away from the region to which dots of the ink are applied.

[0133] As a method of applying the colorless or pale-colored liquidcomposition to the recording medium, it is considered to apply theliquid composition to the whole surface of the recording medium by asprayer, roller or the like. However, the application is preferablycarried out by an ink-jet system by which the liquid composition can beapplied selectively and evenly only to the image-forming region wherethe ink will be applied, and the vicinity of the image-forming region.

[0134] No particular limitation is imposed on the time required from thetime the liquid composition is applied to the recording medium up to thetime the ink is then applied. In order to carry out the presentinvention more effectively, however, it is preferable to apply the inkwithin several seconds, particularly preferably, within 1 second. Thesame shall apply to the case where the ink is first applied to arecording medium, and the colorless or pale-colored liquid compositionis then applied.

[0135] As the method of applying the colorless or pale-colored liquidcomposition to the recording medium, various kinds of ink-jet recordingsystems may be used. However, the so-called On-Demand type thermalink-jet system in which bubbles generated by thermal energy are used toeject droplets is particularly preferred.

[0136] Recording apparatus useful in the practice of the presentinvention will then be described. In the present invention, theso-called On-Demand type thermal ink-jet system in which a recordingsignal is applied to a recording ink in a recording head to ejectdroplets of the ink by the thermal energy generated is preferred.Examples of the construction of a recording head, which is a maincomponent of such an apparatus, are illustrated in FIGS. 1, 2 and 3.

[0137] A head 13 is formed by bonding a glass, ceramic, plastic plate orthe like having an ink-passing channel to a heating head 15, which isused for thermal recording and has a heating resistor (the drawing showsa head to which, however, is not limited). The heating head 15 iscomposed of a protective film 16 made of silicon oxide or the like,aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 made ofnichrome or the like, a heat accumulating layer 19, and a substrate 20made of alumina or the like having a good heat radiating property.

[0138] A recording ink 21 comes up to an ejection orifice 22 and forms ameniscus 23 owing to a pressure P.

[0139] Now, upon application of electric signals to the electrodes 17-1,17-2, the heating head 15 rapidly generates heat at the region shown byn to form bubbles in the ink 21 which is in contact with this region.The meniscus 23 of the ink is projected by the action of the pressurethus produced, and the ink 21 is ejected from the orifice 22 to arecording medium 25 in the form of recording droplets 24. FIG. 3schematically illustrates a multi-head composed of an array of a numberof heads as shown in FIG. 1. The multi-head is formed by closely bondinga glass plate or the like 27 having a number of channels to a heatinghead 28 similar to the head as illustrated in FIG. 1.

[0140] Incidentally, FIG. 1 is a cross-sectional view of the head 13taken along the flow path of the ink, and FIG. 2 is a cross-sectionalview taken along line 2-2′ in FIG. 1.

[0141]FIG. 4 illustrates an exemplary ink-jet recording apparatus inwhich such a head has been incorporated.

[0142] In FIG. 4, reference numeral 61 designates a blade serving as awiping member, one end of which is a stationary end held by ablade-holding member to form a cantilever. The blade 61 is provided at aposition adjacent to a region in which a recording head operates, and inthis embodiment, is held in such a form that it protrudes to the coursethrough which the recording head is moved. Reference numeral 62indicates a cap, which is provided at a home position adjacent to theblade 61, and is so constituted that it moves in a directionperpendicular to a direction in which the recording head is moved andcomes into contact with the face of ejection openings to cap it.Reference numeral 63 denotes an ink-absorbing member providedadjoiningly to the blade 61 and, similar to the blade 61, held in such aform that it protrudes to the course through which the recording head ismoved. The above-described blade 61, cap 62 and absorbing member 63constitute an ejection-recovery portion 64, where the blade 61 andabsorbing member 63 remove water, dust and/or the like from the face ofthe ink-ejecting openings.

[0143] Reference numeral 65 designates the recording head having anejection-energy-generating means and serving to eject the ink onto arecording medium set in an opposing relation with the ejection openingface provided with ejection openings to conduct recording. Referencenumeral 66 indicates a carriage on which the recording head 65 ismounted so that the recording head 65 can be moved. The carriage 66 isslidably interlocked with a guide rod 67 and is connected (notillustrated) at its part to a belt 69 driven by a motor 68. Thus, thecarriage 66 can be moved along the guide rod 67 and hence, the recordinghead 65 can be moved from a recording region to a region adjacentthereto.

[0144] Reference numerals 51 and 52 denote a paper feeding part fromwhich the recording media are separately inserted, and paper feedrollers driven by a motor (not illustrated), respectively. With suchconstruction, the recording medium is fed to the position opposite tothe ejection opening face of the recording head, and discharged from apaper discharge section provided with paper discharge rollers 53 withthe progress of recording.

[0145] In the above constitution, the cap 62 in the head recoveryportion 64 is receded from the moving course of the recording head 65when the recording head 65 is returned to its home position, forexample, after completion of recording, and the blade 61 remainsprotruded to the moving course. As a result, the ejection opening faceof the recording head 65 is wiped. When the cap 62 comes into contactwith the ejection opening face of the recording head 65 to cap it, thecap 62 is moved so as to protrude to the moving course of the recordinghead.

[0146] When the recording head 65 is moved from its home position to theposition at which recording is started, the cap 62 and the blade 61 areat the same positions as the positions upon the wiping as describedabove. As a result, the ejection opening face of the recording head 65is also wiped at the time of this movement.

[0147] The above movement of the recording head to its home position ismade not only when the recording is completed or the recording head isrecovered for ejection, but also when the recording head is movedbetween recording regions for the purpose of recording, during which itis moved to the home position adjacent to each recording region at givenintervals, where the ejection opening face is wiped in accordance withthis movement.

[0148]FIG. 5 illustrates an exemplary ink cartridge in which an ink tobe fed to the head through an ink-feeding member, for example, a tube iscontained. Here, reference numeral 40 designates an ink containerportion containing the ink to be fed, as exemplified by a bag for theink. One end thereof is provided with a stopper 42 made of rubber. Aneedle (not illustrated) may be inserted into this stopper 42 so thatthe ink in the bag 40 for the ink can be fed to the head. Referencenumeral 44 indicates an ink absorbing member for receiving a waste ink.

[0149] It is preferable that the ink container portion is formed of apolyolefin, in particular, polyethylene, at its surface with which theink comes into contact.

[0150] The ink-jet recording apparatus used in the present invention maynot be limited to the apparatus as described above in which the head andthe ink cartridge are separately provided. Therefore, a device in whichthese members are integrally formed as shown in FIG. 6 can also bepreferably used.

[0151] In FIG. 6, reference numeral 70 designates a recording unit, inthe interior of which an ink container portion containing an ink, forexample, an ink-absorbing member, is contained. The recording unit 70 isso constructed that the ink in such an ink-absorbing member is ejectedin the form of ink droplets through a head 71 having a plurality oforifices. For example, polyurethane may be used as a material for theink-absorbing member. Reference numeral 72 indicates an air passage forcommunicating the interior of the recording unit 70 with the atmosphere.This recording unit 70 can be used in place of the recording head shownin FIG. 4, and is detachably installed on the carriage 66. Incidentally,in the recording apparatus used in the present invention, the ink-jetrecording apparatus in which thermal energy is applied to an ink toeject droplets of the ink has been described by way of example. However,the present invention can also be used in other ink-jet recordingapparatus such as a piezo-system using a piezoelectric element.

[0152] In the case where the image-forming process according to thepresent invention is carried out, for example, a recording apparatus inwhich five recording heads, each of which has been illustrated in FIG.3, are arranged on a carriage 80, is used. An example thereof isillustrated in FIG. 7. Reference numerals 81, 82, 83 and 84 indicaterecording heads for ejecting inks of yellow, magenta, cyan and blackcolors, respectively. Reference numeral 85 designates a head forejecting the liquid composition. The heads are arranged in theabove-described recording apparatus and serve to eject the respectiverecording inks of the different colors according to recording signals.Before the ejection of the inks, the liquid composition is applied inadvance to at least portions of recording paper where the recording inksof the different colors are to apply thereto. FIG. 7 shows the casewhere the five recording heads have been used. However, the presentinvention is not limited thereto. As shown in FIG. 8, preference isgiven even to the case where the flow paths of the yellow, magenta, cyanand black inks and the liquid composition are separately provided in onerecording head.

[0153] It goes without saying that construction of the head may bechanged so as to reverse the recording order of the liquid compositionand the inks as described above.

[0154] The present invention will hereinafter be described morespecifically by the following examples and comparative examples.Incidentally, all designations of “part” or “parts” and “%” as will beused in the following examples mean part or parts by weight and % byweight unless expressly noted.

EXAMPLES 1 TO 42

[0155] [Preparation of Colorless or Pale-colored Liquid Composition]

[0156] The following respective components were mixed into solutions,and the resultant solutions were then filtered under pressure through amembrane filter (Fluoropore Filter, trade name: product of SumitomoElectric Industries, Ltd.) having a pore size of 0.22 μm, therebyobtaining colorless or pale-colored Liquid Compositions I_(A) throughI_(H). pHs of the Liquid Compositions I_(A) to I_(H) were adjusted bytreating the respective solutions with NaOH or HCl after the preparationthereof.

[0157] Composition of Liquid Composition I_(A): Composition of LiquidComposition I_(A): Benzyltri-n-butylammonium chloride 1.5 parts (productof Tokyo Kasei Kogyo Co., Ltd.) Sanflock N-500P (polyacrylamide, 0.5part product of Sanyo Chemical Industries, Ltd.) Thiodiglycol 10 partsDeionized water 88 parts pH of I_(A) = 7.0. Composition of LiquidComposition I_(B): Benzalkonium chloride (product of 0.5 parts SanyoChemical Industries, Ltd.) Polyacrylamide (synthesized in our 3.0 partscompany) Thiodiglycol 10 parts Deionized water 86.5 parts pH of I_(B) =4.8. Composition of Liquid Composition I_(C): Benzalkonium chloride(product of 1.5 parts Sanyo Chemical Industries, Ltd.) Polyvinyl alcohol(synthesized in our 10 parts company, Mw = 2,500, completesaponification) Thiodiglycol 10 parts Deionized water 78.5 parts pH ofI_(C) = 4.8. Composition of Liquid Composition I_(D): Benzalkoniumchloride (product of 1.5 parts Sanyo Chemical Industries, Ltd.)Polyvinyl alcohol (synthesized in our 5 parts company, Mw = 9,000,complete saponification) Thiodiglycol 10 parts Deionized water 83.5parts pH of I_(D) = 4.9. Composition of Liquid Composition I_(E):Benzalkonium chloride (product of 1.5 parts Sanyo Chemical Industries,Ltd.) Polyvinyl alcohol (synthesized in our 1 part company, Mw = 26,000,complete saponification) Thiodiglycol 10 parts Deionized water 87.5parts pH of I_(E) = 7.5. Composition of Liquid Composition I_(F):Benzalkonium chloride (product of 1.5 parts Sanyo Chemical Industries,Ltd.) PVP K-15 (product of International 5 parts Specialty Chemicals, Mw= 7,000) Thiodiglycol 10 parts Deionized water 83.5 parts pH of I_(F) =5.0. Composition of Liquid Composition I_(G): Levon TM-16(cetyltrimethylammonium 3.0 parts chloride, product of Sanyo ChemicalIndustries, Ltd.) PVP K-15 (product of International 3 parts SpecialtyChemicals, Mw = 7,000) Thiodiglycol 10 parts Deionized water 84.0 partspH of I_(G) = 4.5. Composition of Liquid Composition I_(H): Levon 15(sodium alkyl diaminoethyl- 1.5 parts glycinate, the alkyl group is alauryl group, product of Sanyo Chemical Industries, Ltd.) PVP K-15(product of International 3 parts Specialty Chemicals, Mw = 7,000)Thiodiglycol 10 parts Deionized water 85.5 parts pH of I_(H) = 3.2.

[0158] Composition of Liquid Composition I_(B): Benzalkonium chloride(product of 0.5 parts Sanyo Chemical Industries, Ltd.) Polyacrylamide(synthesized in our 3.0 parts company) Thiodiglycol 10 parts Deionizedwater 86.5 parts pH of I_(B) = 4.8.

[0159] Composition of Liquid Composition I_(C): Benzalkonium chloride(product of 1.5 parts Sanyo Chemical Industries, Ltd.) Polyvinyl alcohol(synthesized in our 10 parts company, Mw = 2,500, completesaponification) Thiodiglycol 10 parts Deionized water 78.5 parts pH ofI_(C) = 4.8.

[0160] Composition of Liquid Composition I_(D): Benzalkonium chloride(product of 1.5 parts Sanyo Chemical Industries, Ltd.) Polyvinyl alcohol(synthesized in our 5 parts company, Mw = 9,000, completesaponification) Thiodiglycol 10 parts Deionized water 83.5 parts pH ofI_(D) = 4.9.

[0161] Composition of Liquid Composition I_(E): Benzalkonium chloride(product of 1.5 parts Sanyo Chemical Industries, Ltd.) Polyvinyl alcohol(synthesized in our 1 part company, Mw = 26,000, completesaponification) Thiodiglycol 10 parts Deionized water 87.5 parts pH ofI_(E) = 7.5.

[0162] Composition of Liquid Composition I_(F): Benzalkonium chloride(product of 1.5 parts Sanyo Chemical Industries, Ltd.) PVP K-15 (productof International 5 parts Specialty Chemicals, Mw = 7,000) Thiodiglycol10 parts Deionized water 83.5 parts pH of I_(F) = 5.0.

[0163] Composition of Liquid Composition I_(G): Levon TM-16(cetyltrimethylammonium 3.0 parts chloride, product of Sanyo ChemicalIndustries, Ltd.) PVP K-15 (product of International 3 parts SpecialtyChemicals, Mw = 7,000) Thiodiglycol 10 parts Deionized water 84.0 partspH of I_(G) = 4.5.

[0164] Composition of Liquid Composition I_(H): Levon 15 (sodium alkyldiaminoethyl- 1.5 parts glycinate, the alkyl group is a lauryl group,product of Sanyo Chemical Industries, Ltd.) PVP K-15 (product ofInternational 3 parts Specialty Chemicals, Mw = 7,000) Thiodiglycol 10parts Deionized water 85.5 parts pH of I_(H) = 3.2. [Preparation ofRecording Ink] (Preparation of Recording Ink l₁)

[0165] The following respective components were mixed into solutions,and the resultant solutions were filtered under pressure through amembrane filter (Fluoropore Filter, trade name: product of SumitomoElectric Industries, Ltd.) having a pore size of 0.22 μm, therebyobtaining Recording Ink 1₁ composed of yellow, magenta, cyan and blackinks. Yellow Ink Y1₁ of Recording Ink 1₁: C.I. Direct Yellow 86 2 partsThiodiglycol 10 parts Acetylenol EH (EO adduct of acetylene 0.05 partglycol, product of Kawaken Fine Chemicals Co., Ltd.) Deionized water87.95 parts.

[0166] Cyan Ink C1₁ of Recording Ink 1₁:

[0167] The same composition as that of Yellow Ink Y1₁ except that C.I.Direct Yellow 86 in Y1₁ was changed to 2.5 parts of C.I. Direct Blue199, and the amount of deionized water was changed to 87.45 parts.

[0168] Magenta Ink M1₁ of Recording Ink 1₁:

[0169] The same composition as that of Cyan Ink C1₁ except that C.I.Direct Blue 199 in C1₁ was changed to 2.5 parts of C.I. Acid Red 289.

[0170] Black Ink Bk1₁ of Recording Ink 1₁:

[0171] The same composition as that of Magenta Ink M1₁ except that 2.5parts of C.I. Acid Red 289 in Y1₁ were changed to 4.0 parts of C.I. FoodBlack 2, and the amount of deionized water was changed to 85.95 parts.

[0172] (Preparation of Recording Ink 1₂)

[0173] Recording Ink 1₂ composed of inks Y1₂, M1₂, C1₂ and Bk1₂ havingyellow, magenta, cyan and black colors, respectively, was prepared inexactly the same manner as in the preparation of Recording Ink 1₁composed of Y1₁, M1₁, C1₁ and Bk1₁ except that a styrene-acrylic acidcopolymer (Johncryl 61J, trade name, product of Johnson Company, Ltd.,Mw=10,000) was added in an amount of 0.5 part to the respective inks ofRecording Ink 1₁, and the amount of deionized water in each ink wascontrolled in such a manner that the total amount of the ink amounted to100 parts.

[0174] (Preparation of Recording Ink 1₃)

[0175] Recording ink 1₃ composed of inks Y1₃, M1₃, C1₃ and Bk1₃ havingyellow, magenta, cyan and black colors, respectively, was prepared inexactly the same manner as in the preparation of Recording Ink 1₁composed of Y1₁, M1l, C1₁ and Bk1₁ except that an anionic surfactant(Emal D, trade name, product of Kao Corporation, sodium lauryl sulfate)was added in an amount of 1.0 part to the respective inks of RecordingInk 1₁, and the amount of deionized water in each ink was controlled insuch a manner that the total amount of the ink amounted to 100 parts.

[0176] (Preparation of Recording Ink 1₄)

[0177] Yellow Ink Y1₄ of Recording Ink 1₄:

[0178] An alkali-soluble resin (styrene-acrylic acid-ethyl acrylate;acid value: 160; weight average molecular weight: 8,000) was used as adispersant to prepare the following dispersion for a yellow ink.Incidentally, monoethanolamine was used as a neutralizer for thealkali-soluble resin. Aqueous alkali-soluble resin 35 parts solution P1₁(solids content: 20%) C.I. Pigment Yellow 86 24 parts Triethylene glycol10 parts Diethylene glycol 10 parts Ethylene glycol monobutyl ether 1.0part Isopropyl alcohol 0.5 part Deionized water 135 parts.

[0179] The above components were charged in a batch-wise vertical sandmill (manufactured by Aimex Company), and glass beads having a diameterof 1 mm were charged as a grinding medium to conduct a dispersiontreatment for 3 hours while cooling with water. The dispersion wascentrifuged to remove coarse particles, thereby obtaining a dispersionhaving an average particle size of 100 μm.

[0180] After 100 parts of deionized water were added to the dispersion,the mixture was thoroughly stirred to obtain Yellow Ink Y1₄ of pH 9.5.

[0181] Cyan Ink C1₄ of Recording Ink 1₄:

[0182] The same aqueous alkali-soluble resin solution P1₁ as that usedin the preparation of Y1₄ was used. After the following components weremixed, a dispersion treatment was conducted under the same conditions asin the preparation of Y1₄. Aqueous alkali-soluble resin 30 partssolution P1₁ (solids content: 20%) C.I. Pigment Blue 15:3 24 partsTriethylene glycol 10 parts Diethylene glycol 10 parts Ethylene glycolmonobutyl ether 1.0 part Isopropyl alcohol 3 parts Deionized water 135parts.

[0183] The thus-obtained dispersion had an average particle size of 120nm.

[0184] After 100 parts of deionized water were added to the dispersion,the mixture was thoroughly stirred to obtain Cyan Ink C1₄ of pH 9.2.

[0185] Magenta Ink M1₄ of Recording Ink 1₄:

[0186] The same aqueous alkali-soluble resin solution P1₁ as that usedin the preparation of Y1₄ was used. After the following components weremixed, a dispersion treatment was conducted under the same conditions asin the preparation of Y1₄. Aqueous alkali-soluble resin 20 partssolution P1₁ (solids content: 20%) C.I. Pigment Red 122 24 partsGlycerol 15 parts Isopropyl alcohol 3 parts Deionized water 135 parts.

[0187] The thus-obtained dispersion had an average particle size of 115nm.

[0188] After 100 parts of deionized water were added to the dispersion,the mixture was thoroughly stirred to obtain Magenta Ink M1₄ of pH 9.4.

[0189] Black Ink Bk1₁ of Recording Ink 1₄:

[0190] The following components were mixed and heated to 70° C. on awater bath, thereby completely dissolving a resin. Styrene-acrylicacid-ethyl acrylate 1.5 parts copolymer (acid value: 160; weight averagemolecular weight: 8,000) Monoethanolamine 1.2 parts Deionized water 81.5parts.

[0191] To this solution, were added 10 parts of carbon black (MCF 88,product of Mitsubishi Chemical Industries Limited) and 1 part ofisopropyl alcohol to premix them for 30 minutes. Thereafter, theresultant premix was subjected to a dispersion treatment under thefollowing conditions: Dispersing machine: Sand Grinder (manufactured byIgarashi Kikai K.K.) Grinding medium: zirconium beads Packing rate ofthe grinding medium: 50% (by volume) Grinding time: 3 hours.

[0192] The dispersion was further subjected to a centrifugal treatment(12,000 rpm, 20 minutes) to remove coarse particles into a dispersion.

[0193] The following components were then mixed to obtain Black Ink Bk1₄of pH 9.5. Dispersion described above 30 parts Glycerol 10 partsEthylene glycol 5 parts N-Methylpyrrolidone 5 parts Isopropyl alcohol 2parts Deionized water 48 parts.

[0194] (Preparation of Recording Ink 1₅)

[0195] Inks of yellow, magenta, cyan and black colors were prepared inexactly the same manner as in the preparation of Recording Ink 1₄ exceptthat the dispersant in Recording Ink 1₄ was changed to an equiamount ofpolyvinyl pyrrolidone PVP K-15 (product of International SpecialtyChemicals, Mw=7,000).

[0196] Then, an anionic surfactant (Emal D, trade name, product of KaoCorporation, sodium lauryl sulfate) was added to the thus-obtained inksin a proportion of 1.0 part per 100 parts of the respective inks, andthe resultant mixtures were thoroughly mixed, thereby obtainingRecording Ink 1₅ composed of inks Y1₅, M1₅, C1₅ and Bk1₅ having yellow,magenta, cyan and black colors, respectively.

[0197] Using the combinations of the thus-obtained liquid compositionsand recording inks as ink sets, recording was then conducted on CanonPPC paper. As an ink-jet recording apparatus, was used a recordingapparatus similar to that shown in FIG. 4. Color images were formedusing 5 recording heads as illustrated in FIG. 7. Incidentally, theindividual recording heads used had a recording density of 360 dpi, andwere driven with a drive frequency of 5 kHz. In view of the ejectionvolume per dot, heads from which an ink can be ejected at a rate of 40pl/dot was used for the yellow, magenta and cyan inks and the liquidcompositions, while a head from which an ink can be ejected at a rate of80 pl/dot was used for the black inks using a dye as a coloringmaterial, or a head from which an ink can be ejected at a rate of 60pl/dot was used for the black inks using a pigment as a coloringmaterial.

[0198] Printing was performed in accordance with the combinations of thecolorless or pale-colored liquid compositions and the recording inks andtheir printing order shown in Table 1. TABLE 1 Liquid Examplecomposition Ink Printing process 1 I_(A) 1₁ Ejecting I_(A) first 2 I_(A)1₁ Ejecting I_(A) later 3 I_(B) 1₁ Ejecting I_(B) first 4 I_(B) 1₁Ejecting I_(B) later 5 I_(B) 1₄ Ejecting I_(B) first 6 I_(B) 1₄ EjectingI_(B) later 7 I_(C) 1₁ Ejecting I_(C) first 8 I_(C) 1₁ Ejecting I_(C)later 9 I_(C) 1₄ Ejecting I_(C) first 10 I_(C) 1₄ Ejecting I_(C) later11 I_(D) 1₁ Ejecting I_(D) first 12 I_(D) 1₁ Ejecting I_(D) later 13I_(D) 1₄ Ejecting I_(D) first 14 I_(D) 1₄ Ejecting I_(D) later 15 I_(E)1₁ Ejecting I_(E) first 16 I_(E) 1₁ Ejecting I_(E) later 17 I_(E) 1₄Ejecting I_(E) first 18 I_(E) 1₄ Ejecting I_(E) later 19 I_(F) 1₁Ejecting I_(F) first 20 I_(F) 1₁ Ejecting I_(F) later 21 I_(F) 1₂Ejecting I_(F) first 22 I_(F) 1₂ Ejecting I_(F) later 23 I_(F) 1₃Ejecting I_(F) first 24 I_(F) 1₃ Ejecting I_(F) later 25 I_(F) 1₄Ejecting I_(F) first 26 I_(F) 1₄ Ejecting I_(F) later 27 I_(F) 1₅Ejecting I_(F) first 28 I_(F) 1₅ Ejecting I_(F) later 29 I_(G) 1₁Ejecting I_(G) first 30 I_(G) 1₁ Ejecting I_(G) later 31 I_(G) 1₂Ejecting I_(G) first 32 I_(G) 1₂ Ejecting I_(G) later 33 I_(G) 1₃Ejecting I_(G) first 34 I_(G) 1₃ Ejecting I_(G) later 35 I_(G) 1₄Ejecting I_(G) first 36 I_(G) 1₄ Ejecting I_(G) later 37 I_(G) 1₅Ejecting I_(G) first 38 I_(G) 1₅ Ejecting I_(G) later 39 I_(H) 1₁Ejecting I_(H) first 40 I_(H) 1₁ Ejecting I_(H) later 41 I_(H) 1₄Ejecting I_(H) first 42 I_(H) 1₄ Ejecting I_(H) later

[0199] The resultant recorded images were evaluated in accordance withthe following methods.

[0200] 1. Image Density:

[0201] After a solid image was formed with the combination of the liquidcomposition and the black ink in each ink set and left over for 12hours, its reflection density was measured by a reflection densitometer,Macbeth RD915 (manufactured by Macbeth Company) and ranked in accordancewith the following standard:

[0202] AA: Reflection density was not lower than 1.30;

[0203] A: Reflection density was not lower than 1.25 but lower than1.30;

[0204] B: Reflection density was not lower than 1.15 but lower than1.25;

[0205] C: Reflection density was lower than 1.15.

[0206] 2. Fixing Ability:

[0207] After a solid print image of a red color was formed with thecombination of the liquid composition and the yellow and magenta inks ineach ink set, another white paper sheet was placed on the recorded imageby its own weight, thereby measuring the time required until therecorded image no longer transferred to the back side of the paper sheetand no greasing occurred assuming that the time the recording wascompleted was zero. The time measured was used as a measure of thefixing ability to rank it in accordance with the following standard:

[0208] AA: Shorter than 20 seconds;

[0209] A: Not shorter than 20 but shorter than 30 seconds;

[0210] B: Not shorter than 30 but shorter than 40 seconds;

[0211] C: Not shorter than 40.

[0212] 3. Quality of Character:

[0213] Black English characters and numerals were printed with thecombination of the liquid composition and the black ink in each ink setto visually evaluate the quality of character. The quality of characterwas ranked as AA where feathering was scarcely conspicuous, A wherefeathering was somewhat conspicuous, but no problem arose from theviewpoint of practical use, or C where the level was lower than theabove.

[0214] 4. Resistance to Bleeding:

[0215] Solid print images of yellow, magenta, cyan and black colors wereprinted in contiguity with one another with the combinations of theliquid composition and the yellow, magenta, cyan and black inks in eachink set in accordance with the same printing mode as the printing mode E(1 pass, one-direction printing) in a Color Bubble Jet Printer BJC-820(trade name, manufactured by Canon Inc.), thereby visually observing thedegree of bleeding at portions of boundaries between the inks ofdifferent colors. The resistance to bleeding was ranked as AA wherebleeding scarcely occurred, A where bleeding slightly occurred, but noproblem arose from the viewpoint of practical use, or C where the levelwas lower than the above.

[0216] 5. Water Fastness:

[0217] After solid print images and English characters and numerals ofyellow, magenta, cyan and black colors were printed with thecombinations of the liquid composition and the yellow, magenta, cyan andblack inks in each ink set, and the resulting print samples were leftover for 1 hour, they were immersed for 10 seconds in tap water of 20°C. Thereafter, they were taken out of the water, and filter paper waslightly pressed against the print samples to remove water from thesurfaces of the recorded images. The print samples were then air-driedas they are to visually evaluate the images in water fastness. Among theyellow, magenta, cyan and black inks, the ink poorest in water fastnesswas taken as the evaluation result of water fastness. The water fastnesswas ranked in accordance with the following standard:

[0218] AA: No ink running toward the blank portion of the recordingmedium occurred, greasing was scarcely recognized, and blurring of theEnglish characters and numerals also scarcely occurred;

[0219] A: Ink running toward the blank portion of the recording mediumslightly occurred, and the English characters and numerals were somewhatblurred, but no problem arose from the viewpoint of practical use;

[0220] C: Ink running toward the blank portion of the recording mediumoccurred to a significant extent, greasing was also markedly recognized,and marked blurring of the English characters and numerals alsooccurred.

[0221] In all the above examples and following comparative examples, aregion of the recording medium, to which the liquid composition isapplied, corresponds to the image-forming region with the inks. Theprinting duty is 100% in each of the liquid compositions and the inks.The results of the evaluation as to the print samples in Examples 1 to42 are shown collectively in Table 2.

COMPARATIVE EXAMPLES 1 TO 5

[0222] Printing tests and evaluation were performed in exactly the samemanner as in Examples 1 to 42 except that Inks 1₁ to 1₅ were separatelyused, but no liquid composition was used. The results are shown in Table3.

COMPARATIVE EXAMPLE 6

[0223] A colorless or pale-colored Liquid composition composed of thefollowing components was prepared, and printing tests and evaluationwere conducted in the same manner as in Examples 1 to 42 except thatthis liquid composition and the same inks as those used in Example 1were used. Benzyltributylainmonium chloride 1.5 parts Thiodiglycol 10parts Surfactant (Acetyleriol EH, product of 0.5 part Kawaken FineChemicals Co., Ltd.) Deionized water 88 parts

[0224] The results are shown in Table 3. TABLE 2 Image Fixing Quality ofResistance Water Ex. density ability character to bleeding fastness 1 AA A A A 2 A A A A A 3 AA AA AA AA A 4 AA A A A A 5 AA A AA AA AA 6 AA AA AA AA 7 AA AA AA AA A 8 AA A A A A 9 AA A AA AA AA 10 AA A A AA AA 11AA AA AA AA A 12 AA A A A AA 13 AA A AA AA AA 14 AA A A AA A 15 A A A AA 16 A A A A A 17 A A AA AA AA 18 A A A AA AA 19 AA AA AA AA A 20 AA A AA A 21 AA A A AA AA 22 AA A A AA AA 23 AA AA AA AA AA 24 AA AA A AA AA25 AA A AA AA AA 26 AA A A AA AA 27 AA AA AA AA AA 28 AA AA AA A AA 29AA A AA AA A 30 AA A A A A 31 AA A AA AA AA 32 AA A A A AA 33 AA AA AAAA AA 34 AA AA A A AA 35 AA A AA AA AA 36 AA A A AA AA 37 AA AA AA AA AA38 AA AA A AA AA 39 A AA AA AA A 40 A AA A A A 41 AA A AA AA AA 42 AA AA AA AA

[0225] TABLE 3 Comp. Image Fixing Quality of Resistance Water Ex.density ability character to bleeding fastness 1 AA B AA C C 2 AA B AA CC 3 B AA C C C 4 C C AA C AA 5 C C AA C AA 6 B B C C C

[0226] The present invention will hereinafter be described in moredetail by other examples and comparative examples. Incidentally, theweight average molecular weights of the dispersants in the pigment inksin the following examples were determined by the GPC method using astyrene polymer as a standard.

EXAMPLE 43

[0227] The following components were first mixed into a solution, andthe resultant solution was then filtered under pressure through amembrane filter (Fluoropore Filter, trade name: product of SumitomoElectric Industries, Ltd.) having a pore size of 0.22 μm, therebyobtaining a colorless Liquid Composition II_(A) the pH of which wasadjusted to 4.8.

[0228] Components of Liquid Composition II_(A): Polyallylaminehydrochloride 5.0 parts (peak of molecular weight distribution in termsof polyoxyethylene oxide: 800) Nonionic polymer, PVP-K-15 5.0 parts(polyvinyl pyrrolidone, Mw = 7,000) Thiodiglycol 10.0 parts Deionizedwater 80.0 parts.

[0229] (Preparation of Ink 2₁)

[0230] The following respective components were then mixed intosolutions, and the resultant solutions were separately filtered underpressure through a membrane filter (Fluoropore Filter, trade name:product of Sumitomo Electric Industries, Ltd.) having a pore size of0.22 μm, thereby obtaining a yellow ink Y2₁, a magenta ink M2₁, a cyanink C2₁ and a black ink Bk2₁, which were adjusted to pH 4.8 andcontained their corresponding dyes having an anionic group. These inkswere called Ink 2₁ collectively.

[0231] Yellow Ink Y2₁: C.I. Direct Yellow 86 2 parts Thiodiglycol 10parts EO adduct of acetylene glycol 0.05 part (Acetylenol EH, product ofKawaken Fine Chemicals Co., Ltd.) Deionized water 87.95 parts.

[0232] Magenta Ink M2₁: C.I. Acid Red 289 2.5 parts Thiodiglycol 10parts EO adduct of acetylene glycol 0.05 part (Acetylenol EH, product ofKawaken Fine Chemicals Co., Ltd.) Deionized water 87.45 parts.

[0233] Cyan Ink C2₁: C.I. Direct Blue 199 2.5 parts Thiodiglycol 10parts EO adduct of acetylene glycol 0.05 part (Acetylenol EH, product ofKawaken Fine Chemicals Co., Ltd.) Deionized water 87.45 parts.

[0234] Black Ink Bk2 C.I. Food Black 2 4.0 parts Thiodiglycol 10 partsEO adduct of acetylene glycol 0.05 part (Acetylenol EH, product ofKawaken Fine Chemicals Co., Ltd.) Deionized water 85.95 parts.

[0235] Using, as an ink set, the combination of the thus-obtained LiquidComposition II_(A) and Ink 2₁ according to this example, recording wasthen conducted on PPC paper (product of Canon Inc.). As an ink-jetrecording apparatus, was used a recording apparatus similar to thatshown in FIG. 4. Color images were formed using 5 recording heads asillustrated in FIG. 7. In this recording, Liquid Composition II_(A) wasfirst ejected to apply it to the recording paper in advance, after whichInk 2₁ was applied. Incidentally, individual recording heads used inthis example had a recording density of 360 dpi, and were driven with adrive frequency of 5 kHz. In view of the ejection volume per dot, headsfrom which an ink can be ejected at a rate of 40 pl/dot was used for theyellow, magenta and cyan inks and the liquid composition, while a headfrom which an ink can be ejected at a rate of 80 pl/dot was used for theblack ink.

[0236] Incidentally, these recording conditions are the same throughoutexamples and comparative examples, which will be described subsequentlyand use inks containing a dye. The environmental conditions uponprinting tests were controlled to 25° C. and 55% RH.

EXAMPLE 44

[0237] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(A) andInk 2₁ using a dye as a coloring material, which had been used inExample 43, was used as an ink set according to this example, and Ink 2₁was first applied to the recording paper and Liquid Composition II_(A)was then ejected.

EXAMPLE 45

[0238] Liquid Composition II_(B) of this example composed of thefollowing components was first prepared in the same manner as in thepreparation of Liquid Composition II_(A) according to Example 43.Components of Liquid Composition II_(B): Cationic oligomer representedby  5.0 parts the following formula (peak of molecular weightdistribution in terms of polyoxyethylene oxide: 900)

Nonionic polymer, PVP-K-15  5.0 parts (polyvinyl pyrrolidone, Mw =7,000) Thiodiglycol 10.0 parts Deionized water 80.0 parts.

[0239] (Preparation of Ink 2₂)

[0240] Ink 2₂ composed of inks Y2₂, M2₂, C2₂ and Bk2₂ having yellow,magenta, cyan and black colors, respectively, and containing theircorresponding dyes having an anionic group was prepared in the samemanner as in the preparation of Ink 2₁ of Example 43 except that ananionic polymeric substance (Johncryl 61J, styrene-acrylic acidcopolymer, Mw=10,000, product of Johnson Company, Ltd.) was added in anamount of 1.0 part to the respective components of Ink 2₁ used inExample 43, and the amount of water in each ink was controlled in such amanner that the total amount of the components amounted to 100 parts.

[0241] Using, as an ink set, the combination of the thus-prepared LiquidComposition II_(B) and Ink 2₂ according to this example, recording wasthen conducted on PPC paper (product of Canon Inc.) under the sameconditions as in Example 43. In this example, also, Liquid CompositionII_(B) was first ejected to apply it to the recording paper in advance,after which Ink 2₂ was applied to conduct the recording.

EXAMPLE 46

[0242] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(B) andInk 2₂ using a dye as a coloring material, both, used in Example 45, wasused as an ink set according to this example, and Ink 2₂ was firstapplied to the recording paper and Liquid Composition II_(B) was thenejected.

EXAMPLE 47

[0243] Liquid Composition II_(C) of this example composed of thefollowing components was first prepared in the same manner as in thepreparation of Liquid Composition II_(A) according to Example 43.Components of Liquid Composition II_(C): Polyallylamine hydrochloride 5.0 parts (peak of molecular weight distribution in terms ofpolyoxyethylene oxide: 800) Nonionic polymer, PVP-K-15  5.0 parts(polyvinyl pyrrolidone, Mw = 7,000) Thiodiglycol 10.0 parts Benzalkoniumchloride represented by  3.0 parts the following formula

Deionized water 77.0 parts.

[0244] Using, as an ink set, the combination of the thus-prepared LiquidComposition II_(C) according to this example, and Ink 2₁ using a dye asa coloring material, which had been used in Example 43, recording wasthen conducted on PPC paper (product of Canon Inc.) under the sameconditions as in Example 43. In this example, also, Liquid CompositionII_(C) was first ejected to apply it to the recording paper in advance,after which Ink 2₁ was applied to conduct the recording.

EXAMPLE 48

[0245] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(C) andInk 2₁ using a dye as a coloring material, both, used in Example 47, wasused as an ink set according to this example, and Ink 2₁ was firstapplied to the recording paper and Liquid Composition II_(C) was thenejected.

EXAMPLE 49

[0246] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(C) usedin Example 47, and Ink 2₂ using a dye as a coloring material, which hadbeen used in Example 45, was used as an ink set according to thisexample, and Liquid Composition II_(C) was first applied to therecording paper and Ink 2₂ was then applied.

EXAMPLE 50

[0247] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(C) usedin Example 47, and Ink 2₂ using a dye as a coloring material, which hadbeen used in Example 45, was used as an ink set according to thisexample, and Ink 2₂ was first applied to the recording paper and LiquidComposition II_(C) was then ejected.

EXAMPLE 51

[0248] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(C) usedin Example 47, and Ink 2₃ using a dye as a coloring material andobtained in the following manner was used as an ink set according tothis example, and Liquid Composition II_(C) was first applied to therecording paper and Ink 2₃ was then applied.

[0249] (Preparation of Ink 2₃)

[0250] Ink 2₃ composed of inks Y2₃, M2₃, C2₃ and Bk2₃ having yellow,magenta, cyan and black colors, respectively, and containing theircorresponding dyes having an anionic group was prepared in the samemanner as in the preparation of Ink 2₁ of Example 43 except that ananionic surfactant (Emal D, sodium lauryl sulfate, product of KaoCorporation) was added in an amount of 1.0 part to the respectivecomponents of Ink 2₁ used in Example 43, and the amount of deionizedwater in each ink was controlled in such a manner that the total amountof the components amounted to 100 parts.

EXAMPLE 52

[0251] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(C) usedin Example 47, and Ink 2₃ using a dye as a coloring material, which hadbeen used in Example 51, was used as an ink set according to thisexample, and Ink 2₃ was first applied to the recording paper and LiquidComposition II_(C) was then ejected.

EXAMPLE 53

[0252] Liquid Composition II_(D) of this example composed of thefollowing components was first prepared in the same manner as in thepreparation of Liquid Composition II_(A) according to Example 43.Components of liquid composition II_(D): Cationic oligomer representedby  5.0 parts the following formula (peak of molecular weightdistribution in terms of polyoxyethylene oxide: 900)

Nonionic polymer, PVP-K-15  5.0 parts (polyvinyl pyrrolidone, Mw =7,000) Thiodiglycol 10.0 parts Benzalkonium chloride represented by  3.0parts the following formula

Deionized water 77.0 parts.

[0253] Using, as an ink set, the combination of the thus-prepared liquidcomposition II_(D) according to this example, and Ink 2₁ using a dye asa coloring material, which had been used in Example 43, recording wasthen conducted on PPC paper (product of Canon Inc.) under the sameconditions as in Example 43. In this example, also, Liquid CompositionII_(D) was first ejected to apply it to the recording paper in advance,after which Ink 2₁ was applied to conduct the recording.

EXAMPLE 54

[0254] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(D) andInk 2₁ using a dye as a coloring material, both, used in Example 53, wasused as an ink set according to this example, and Ink 2₁ was firstapplied to the recording paper and Liquid Composition II_(D) was thenejected.

EXAMPLE 55

[0255] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(D) usedin Example 53, and Ink 2₂ using a dye as a coloring material, which hadbeen used in Example 45, was used as an ink set according to thisexample, and Liquid Composition II_(D) was first applied to therecording paper and Ink 2₂ was then applied.

EXAMPLE 56

[0256] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(D) usedin Example 53, and Ink 2₂ using a dye as a coloring material, which hadbeen used in Example 45, was used as an ink set according to thisexample, and Ink 2₂ was first applied to the recording paper and LiquidComposition II_(D) was then ejected.

EXAMPLE 57

[0257] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(D) usedin Example 53, and Ink 2₃ using a dye as a coloring material, which hadbeen used in Example 51, was used as an ink set according to thisexample, and Liquid Composition II_(D) was first applied to therecording paper and Ink 2₃ was then applied.

EXAMPLE 58

[0258] Recording was conducted under the same conditions as those inExample 43 except that the combination of Liquid Composition II_(D) usedin Example 53, and Ink 2₃ using a dye as a coloring material, which hadbeen used in Example 45, was used as an ink set according to thisexample, and Ink 2₃ was first applied to the recording paper and LiquidComposition II_(D) was then ejected.

EXAMPLE 59

[0259] Inks Y2₄, M2₄, C2₄ and Bk2₄ having yellow, magenta, cyan andblack colors, respectively, and containing their corresponding pigmentsand an anionic compound were prepared in the following manner. Theseinks were called Ink 2₄ collectively. An ink set of this example wasprepared from Ink 2₄ and Liquid Composition II_(C) used in Example 47.Using this ink set, recording was conducted on PPC paper (product ofCanon Inc.). In this example, Liquid Composition II_(C) was firstejected to apply it to the recording paper in advance, after which Ink2₄ was applied to conduct the recording.

[0260] Individual recording heads used in this example had a recordingdensity of 360 dpi, and were driven with a drive frequency of 5 kHz. Inview of the ejection volume per dot, heads from which an ink can beejected at a rate of 40 pl/dot was used for the yellow, magenta and cyaninks and the liquid composition, while a head from which an ink can beejected at a rate of 60 pl/dot was used for the black ink.

[0261] Incidentally, these recording conditions are the same throughoutexamples, which will be described subsequently and use inks containing apigment. The environmental conditions upon printing tests werecontrolled to 25° C. and 55% RH.

[0262] (Preparation Ink 2₄) Styrene-acrylic acid-ethyl acrylate 1.5parts copolymer (acid value: 140, weight average molecular weight:5,000) Monoethanol amine 1 part Diethylene glycol 5 parts Deionizedwater 81.5 parts

[0263] The above components were mixed, and heated to 70° C. on a waterbath to completely dissolve the resin. To this solution, were added 10parts of carbon black (MCF 88, product of Mitsubishi Chemical IndustriesLimited) and 1 part of isopropyl alcohol to premix them for 30 minutes.Thereafter, the resulting premix was subjected to a dispersion treatmentunder the following conditions: Dispersing machine: Sand Grinder(manufactured by Igarashi Kikai K.K.) Grinding medium: zirconium beads(diameter: 1 mm) Packing rate of the grinding medium: 50% (by volume)Grinding time: 3 hours.

[0264] The dispersion was further subjected to a centrifugal treatment(12,000 rpm, 20 minutes) to remove coarse particles into a dispersion.

[0265] (Preparation of Black Ink)

[0266] The above-prepared dispersion was used, and components of thefollowing compositional proportion were mixed to prepare an inkcontaining the pigment, thereby providing this ink as Black Ink Bk2₄.Dispersion described above 30.0 parts Glycerol 10.0 parts Ethyleneglycol 5.0 parts N-Methylpyrrol idone 5.0 parts Isopropyl alcohol 2.0parts Deionized water 48.0 parts.

[0267] Yellow Ink Y2₄:

[0268] Yellow Ink Y2₄ containing a pigment was prepared in the samemanner as in the preparation of Black Ink Bk2₄ except that 10 parts ofcarbon black (MCF 88, product of Mitsubishi Chemical Industries Limited)used in the preparation of Black Ink Bk2₄ were changed to Pigment Yellow74.

[0269] Magenta Ink M2₄:

[0270] Magenta Ink M2₄ containing a pigment was prepared in the samemanner as in the preparation of Black Ink Bk2₄ except that 10 parts ofcarbon black (MCF 88, product of Mitsubishi Chemical Industries Limited)used in the preparation of Black Ink Bk2₄ were changed to Pigment Red 7.

[0271] Cyan Ink C2₄:

[0272] Cyan Ink C2₄ containing a pigment was prepared in the same manneras in the preparation of Black Ink Bk2₄ except that 10 parts of carbonblack (MCF 88, product of Mitsubishi Chemical Industries Limited) usedin the preparation of Black Ink Bk2₄ were changed to Pigment Blue 15.

EXAMPLE 60

[0273] Recording was conducted under the same conditions as those inExample 59 except that the combination of Liquid Composition II_(C) usedin Example 47, and Ink 2₄ using a pigment as a coloring material, whichhad been used in Example 59, was used as an ink set according to thisexample, and Ink 2₄ was first applied to the recording paper and LiquidComposition II_(C) was then ejected.

EXAMPLE 61

[0274] Recording was conducted under the same conditions as those inExample 59 except that the combination of Liquid Composition II_(D) usedin Example 53, and Ink 2₄ using a pigment as a coloring material, whichhad been used in Example 59, was used as an ink set according to thisexample, and Liquid Composition II_(D) was first applied to therecording paper and Ink 2₄ was then applied.

EXAMPLE 62

[0275] Recording was conducted under the same conditions as those inExample 59 except that the combination of Liquid Composition II_(D) usedin Example 53, and Ink 2₄ using a pigment as a coloring material, whichhad been used in Example 59, was used as an ink set according to thisexample, and Ink 2₄ was first applied to the recording paper and LiquidComposition II_(D) was then ejected.

[0276] [Evaluation]

[0277] The recorded images obtained in Examples 43 to 62, which aresummarized in Table 4, were evaluated in accordance with the methodsdescribed above. The results are shown collectively in Table 5. TABLE 4Liquid Example composition Ink Printing process 43 II_(A) 2₁ EjectingII_(A) first 44 II_(A) 2₁ Ejecting II_(A) later 45 II_(B) 2₂ EjectingII_(B) first 46 II_(B) 2₂ Ejecting II_(B) later 47 II_(C) 2₁ EjectingII_(C) first 48 II_(C) 2₁ Ejecting II_(C) later 49 II_(C) 2₂ EjectingII_(C) first 50 II_(C) 2₂ Ejecting II_(C) later 51 II_(C) 2₃ EjectingII_(C) first 52 II_(D) 2₃ Ejecting II_(D) later 53 II_(D) 2₁ EjectingII_(D) first 54 II_(D) 2₁ Ejecting II_(D) later 55 II_(D) 2₂ EjectingII_(D) first 56 II_(D) 2₂ Ejecting II_(D) later 57 II_(D) 2₃ EjectingII_(D) first 58 II_(D) 2₃ Ejecting II_(D) later 59 II_(C) 2₄ EjectingII_(C) first 60 II_(C) 2₄ Ejecting II_(C) later 61 II_(D) 2₄ EjectingII_(D) first 62 II_(D) 2₄ Ejecting II_(D) later

[0278] TABLE 5 Evaluation results Image Fixing Quality of ResistanceWater Ex. density ability character to bleeding fastness 43 AA A AA AAAA 44 AA A A A AA 45 AA AA AA AA AA 46 AA AA A A AA 47 A AA AA AA AA 48A AA A A AA 49 AA AA AA AA AA 50 AA AA A A AA 51 A AA A AA AA 52 A AA AA AA 53 A AA A AA AA 54 A AA AA A AA 55 AA AA A AA AA 56 AA AA A A AA 57A AA A AA AA 58 A AA A A AA 59 AA A AA AA AA 60 AA A AA A AA 61 AA A AAAA AA 62 AA A AA A AA

[0279] As apparent from Table 5, images excellent in all the fixingability, quality of character, image density, resistance to bleeding andwater fastness were obtained in the examples, while only images low inthe density and poor in the quality of character were provided inComparative Example 6. These images were poor even in the waterfastness.

EXAMPLE 63

[0280] Using Liquid Composition II_(A) used in Example 43 and 3 inks ofYellow Ink Y2₁, Magenta Ink M2₁ and Cyan Ink C2₁ in Ink 2₁ used inExample 43, a solid print image was recorded with each duty controlledto 100%, thereby forming an image of the so-called process black. Theconditions for the printing were exactly the same as those in Example43. In this case, the results of the evaluation as to the image density,fixing ability, quality of character and bleeding at portions ofboundaries between the image of the process black and images of othercolors were all good. Therefore, it was confirmed that the presentinvention is effective.

[0281] The present invention will hereinafter be described in moredetail by further examples and comparative examples.

EXAMPLES 64 TO 109

[0282] [Preparation of Colorless of Pale-colored Liquid Composition]

[0283] The following respective components were mixed into solutions,and the resultant solutions were then filtered under pressure through amembrane filter (Fluoropore Filter, trade name: product of SumitomoElectric Industries, Ltd.) having a pore size of 0.22 μm, therebyobtaining colorless or pale-colored Liquid Compositions III_(A) throughIII_(G).

[0284] Composition of Liquid Composition III_(A):Stearyltrimethylammonium chloride 2 parts (Electrostripper QE, tradename, product of Kao Corporation) Polyamine sulfone hydrochloride 10parts (PAS-A-5, trade name, product of Nitto Boseki Co., Ltd., peak ofmolecular weight distribution: 2,000) Thiodiglycol 10 parts Deionizedwater 78 parts.

[0285] Composition of Liquid Composition III_(B):Stearyltrimethylammonium chloride 2 parts (Electrostripper QE, tradename, product of Kao Corporation) Polyamine sulfone hydrochloride 6parts (PAS-A-5, trade name, product of Nitto Boseki Co., Ltd., peak ofmolecular weight distribution: 3,500) Thiodiglycol 10 parts Deionizedwater 82 parts.

[0286] Composition of Liquid Composition III_(C):Stearyltrimethylammonium chloride 2 parts (Electrostripper QE, tradename, product of Kao Corporation) Polyamine sulfone hydrochloride 4parts (PAS-92, trade name, product of Nitto Boseki Co., Ltd., peak ofmolecular weight distribution: 5,000) Thiodiglycol 10 parts Deionizedwater 84 parts.

[0287] Composition of Liquid Composition III_(D):Stearyltrimethylammonium chloride 2 parts (Electrostripper QE, tradename, product of Kao Corporation) Polyallylamifle hydrochloride 3 parts(synthesized in our company, peak of molecular weight distribution:8,500) Thiodiglycol 10 parts Deionized water 85 parts.

[0288] with the method described in “Kino Zairyo (Functional Material)”,Vol. 5, 29 (1986). The same shall apply to the following examples.

[0289] Composition of Liquid Composition III_(E): Polyallylamine 3 parts(synthesized in our company, peak of molecular weight distribution: 800)Polyamine sulfone hydrochloride 10 parts (PAS-A-1, trade name, productof Nitto Boseki Co., Ltd., peak of molecular weight distribution: 2,000)Thiodiglycol 10 parts Deionized water 77 parts.

[0290] in accordance with the method described in “Kino Zairyo(Functional Material)”, Vol. 5, 29 (1986). The same shall apply to thefollowing examples.

[0291] Composition of Liquid Composition III_(F): Polyallylamine  5parts (synthesized in our company, peak of molecular weightdistribution: 650) Polyallylamine hydrochloride  3 parts (synthesized inour company, peak of molecular weight distribution: 8,500) Thiodiglycol10 parts Deionized water  82 parts.

[0292] Composition of Liquid Composition III_(G): [Preparation ofRecording Ink] Benzyltri-n-butylammonium chloride  3 parts (product ofTokyo Kasei Kogyo Co., Ltd., reagent grade) Polyallylamine hydrochloride 3 parts (synthesized in our company, peak of molecular weightdistribution: 8,500) Thiodiglycol 10 parts Deionized water  84 parts.

[0293] (Preparation of Recording Ink 3₁)

[0294] The following respective components were mixed and then filteredunder pressure through a membrane filter (Fluoropore Filter, trade name:product of Sumitomo Electric Industries, Ltd.) having a pore size of0.22 μm, thereby obtaining Recording Ink 3₁ composed of yellow, magenta,cyan and black inks.

[0295] Yellow Ink Y3 of Recording Ink 3₁: C.I. Direct Yellow 142 2 partsThiodiglycol 10 parts Acetylenol EH (EO adduct of acetylene 0.05 partglycol, product of Kawaken Fine Chemicals Co., Ltd.) Deionized water87.95 parts.

[0296] Cyan Ink C3₁ of Recording Ink 3₁:

[0297] The same composition as that of Yellow Ink Y3₁ except that C.I.Direct Yellow 142 in Y3₁ was changed to 2.5 parts of C.I. Direct Blue199, and the amount of deionized water was changed to 87.45 parts.

[0298] Magenta Ink M3₁ of Recording Ink 3₁:

[0299] The same composition as that of Cyan Ink C3₁ except that C.I.Direct Blue 199 in C3₁ was changed to 2.5 parts of C.I. Acid Red 92.

[0300] Black Ink Bk3₁ of Recording Ink 3₁:

[0301] The same composition as that of Magenta Ink M3₁ except that 2.5parts of C.I. Acid Red 92 in M3₁ were changed to 4.0 parts of C.I. FoodBlack 2, and the amount of deionized water was changed to 85.95 parts.

[0302] (Preparation of Recording Ink 3₂)

[0303] Recording Ink 3₂ composed of inks Y3₂, M3₂, C3₂ and Bk3₂ havingyellow, magenta, cyan and black colors, respectively, was prepared inexactly the same manner as in the preparation of Recording Ink 3₁ ofY3₁, M3₁, C3₁ and Bk3₁ except that a styrene-acrylic acid copolymer(Johncryl 61J, trade name, product of Johnson Company, Ltd., Mw=10,000)was added in an amount of 0.5 part to the respective inks of RecordingInk 3₁ and the amount of deionized water in each ink was controlled insuch a manner that the total amount of the ink amounted to 100 parts.

[0304] (Preparation of Recording Ink 3₃)

[0305] Recording ink 3₃ composed of inks Y3₃, M3₃, C3₃ and Bk3₃ havingyellow, magenta, cyan and black colors, respectively, was prepared inexactly the same manner as in the preparation of Recording Ink 3₁ ofY3₁, M3₁, C3₁ and Bk3₁ except that an anionic surfactant [Viewlight ESS,trade name, product of Sanyo Chemical Industries, Ltd., disodiumpolyoxyethylene alkyl(C₁₂-C₁₆)sulfosuccinate (2E.O)] was added in anamount of 1.0 part to the respective inks of Recording Ink 3₁, and theamount of deionized water in each ink was controlled in such a mannerthat the total amount of the ink amounted to 100 parts.

[0306] (Preparation of Recording Ink 3₄)

[0307] Yellow Ink Y3₄ of Recording Ink 3₄:

[0308] An alkali-soluble resin (styrene-acrylic acid-ethyl acrylate;acid value: 160; weight average molecular weight: 8,000) was used as adispersant to prepare the following dispersion for a yellow ink.Incidentally, monoethanolamine was used as a neutralizer for thealkali-soluble resin. Aqueous alkali-soluble resin 35 parts solution P3₁(solids content: 20%) C.I. Pigment Yellow 83 24 parts Triethylene glycol10 parts Diethylene glycol 10 parts Ethylene glycol monobutyl ether 1.0part Isopropyl alcohol 0.5 part Deionized water 135 parts.

[0309] The above components were charged in a batch-wise vertical sandmill (manufactured by Aimex Company), and glass beads having a diameterof 1 mm were charged as a grinding medium to conduct a dispersiontreatment for 3 hours while cooling with water. The dispersion wascentrifuged to remove coarse particles, thereby obtaining a dispersionhaving an average particle size of 100 nm.

[0310] After 100 parts of deionized water were added to the dispersion,the mixture was thoroughly stirred to obtain Yellow Ink Y3₄ of pH 9.5.

[0311] Cyan Ink C3₄ of Recording Ink 3₄:

[0312] The same aqueous alkali-soluble resin solution P3₁ as that usedin the preparation of Y3₄ was used. After the following components weremixed, a dispersion treatment was conducted under the same conditions asin the preparation of Y3₄. Aqueous alkali-soluble resin 30 partssolution P3₁ (solids content: 20%) C.I. Pigment Blue 15:3 24 partsTriethylene glycol 10 parts Diethylene glycol 10 parts Ethylene glycolmonobutyl ether 1.0 part Isopropyl alcohol 3 parts Deionized water 135parts.

[0313] The thus-obtained dispersion had an average particle size of 120nm.

[0314] After 100 parts of deionized water were added to the dispersion,the mixture was thoroughly stirred to obtain Cyan Ink C3₄ of pH 9.2.

[0315] Magenta Ink M3₄ of Recording Ink 3₄:

[0316] The same aqueous alkali-soluble resin solution P3₁ as that usedin the preparation of Y3₄ was used. After the following components weremixed, a dispersion treatment was conducted under the same conditions asin the preparation of Y3₄. Aqueous alkali-soluble resin 20 partssolution P3₁ (solids content: 20%) C.I. Pigment Red 122 24 partsGlycerol 15 parts Isopropyl alcohol 3 parts Deionized water 135 parts.

[0317] The thus-obtained dispersion had an average particle size of 115nm.

[0318] After 100 parts of deionized water were added to the dispersion,the mixture was thoroughly stirred to obtain Magenta Ink M3₄ of pH 9.4.

[0319] Black Ink Bk3₄ of Recording Ink 3₄:

[0320] The following components were mixed and heated to 70° C. on awater bath, thereby completely dissolving a resin. Styrene-acrylicacid-ethyl acrylate 1.5 parts copolymer (acid value: 160; weight averagemolecular weight: 8,000) Monoethanolamine 1.2 parts Deionized water 81.5parts.

[0321] To this solution, were added 10 parts of carbon black (MCF 88,product of Mitsubishi Chemical Industries Limited) and 1 part ofisopropyl alcohol to premix them for 30 minutes. Thereafter, theresultant premix was subjected to a dispersion treatment under thefollowing conditions: Dispersing machine: Sand Grinder (manufactured byIgarashi Kikai K.K.) Grinding medium: zirconium beads Packing rate ofthe grinding medium: 50% (by volume) Grinding time: 3 hours.

[0322] The dispersion was further subjected to a centrifugal treatment(12,000 rpm, 20 minutes) to remove coarse particles into a dispersion.

[0323] The following components were then mixed to obtain Black Ink Bk3₄of Recording Ink 3₄ having a pH of 9.5. Dispersion described above 30parts Glycerol 10 parts Ethylene glycol 5 parts N-Methylpyrrolidone 5parts Isopropyl alcohol 2 parts Deionized water 48 parts.

[0324] (Preparation of Recording Ink 3₅)

[0325] Inks of yellow, magenta, cyan and black colors were prepared inexactly the same manner as in the preparation of Recording Ink 3₄ exceptthat the dispersant in Recording Ink 3₄ was changed to an equiamount ofpolyvinyl pyrrolidone PVP K-15 (product of International SpecialtyChemicals, MW=7,000).

[0326] Then, an anionic surfactant [Viewlight ESS, trade name, productof Sanyo Chemical Industries, Ltd., disodium polyoxyethylenealkyl(C₁₂-C₁₆)sulfosuccinate (2E.O)] was added to the thus-obtained inksin a proportion of 1.0 part per 100 parts of the respective inks, andthe resultant mixtures were thoroughly mixed, thereby obtainingRecording Ink 3₅ composed of inks Y3₅, M3₅, C3₅ and Bk3₅ having yellow,magenta, cyan and black colors, respectively.

[0327] Using the combinations of the thus-obtained liquid compositionsand recording inks as ink sets, recording was then conducted on CanonPPC paper. As an ink-jet recording apparatus, was used a recordingapparatus similar to that shown in FIG. 4. Color images were formedusing 5 recording heads as illustrated in FIG. 7. Incidentally, theindividual recording heads used had a recording density of 360 dpi, andwere driven with a drive frequency of 5 kHz. In view of the ejectionvolume per dot, heads from which an ink can be ejected at a rate of 40pl/dot was used for the yellow, magenta and cyan inks and the liquidcompositions, while a head from which an ink can be ejected at a rate of80 pl/dot was used for the black inks using a dye as a coloringmaterial, or a head from which an ink can be ejected at a rate of 60pl/dot was used for the black inks using a pigment as a coloringmaterial.

[0328] The printing was performed in accordance with the combinations ofthe colorless or pale-colored liquid compositions and the recording inksand their printing order shown in Table 6. TABLE 6 Liquid Examplecomposition Ink Printing process 64 III_(A) 3₁ Ejecting III_(A) first 65III_(A) 3₁ Ejecting III_(A) later 66 III_(A) 3₄ Ejecting III_(A) first67 III_(A) 3₄ Ejecting III_(A) later 68 III_(B) 3₁ Ejecting III_(B)first 69 III_(B) 3₁ Ejecting III_(B) later 70 III_(B) 3₄ EjectingIII_(B) first 71 III_(B) 3₄ Ejecting III_(B) later 72 III_(C) 3₁Ejecting III_(C) first 73 III_(C) 3₁ Ejecting III_(C) later 74 III_(C)3₄ Ejecting III_(C) first 75 III_(C) 3₄ Ejecting III_(C) later 76III_(D) 3₁ Ejecting III_(D) first 77 III_(D) 3₁ Ejecting III_(D) later78 III_(D) 3₄ Ejecting III_(D) first 79 III_(D) 3₄ Ejecting III_(D)later 80 III_(E) 3₁ Ejecting III_(E) first 81 III_(E) 3₁ EjectingIII_(E) later 82 III_(E) 3₂ Ejecting III_(E) first 83 III_(E) 3₂Ejecting III_(E) later 84 III_(E) 3₃ Ejecting III_(E) first 85 III_(E)3₃ Ejecting III_(E) later 86 III_(E) 3₄ Ejecting III_(E) first 87III_(E) 3₄ Ejecting III_(E) later 88 III_(E) 3₅ Ejecting III_(E) first89 III_(E) 3₅ Ejecting III_(E) later 90 III_(F) 3₁ Ejecting III_(F)first 91 III_(F) 3₁ Ejecting III_(F) later 92 III_(F) 3₂ EjectingIII_(F) first 93 III_(F) 3₂ Ejecting III_(F) later 94 III_(F) 3₃Ejecting III_(F) first 95 III_(F) 3₃ Ejecting III_(F) later 96 III_(F)3₄ Ejecting III_(F) first 97 III_(F) 3₄ Ejecting III_(F) later 98III_(F) 3₅ Ejecting III_(F) first 99 III_(F) 3₅ Ejecting III_(F) later100 III_(G) 3₁ Ejecting III_(G) first 101 III_(G) 3₁ Ejecting III_(G)later 102 III_(G) 3₂ Ejecting III_(G) first 103 III_(G) 3₂ EjectingIII_(G) later 104 III_(G) 3₃ Ejecting III_(G) first 105 III_(G) 3₃Ejecting III_(G) later 106 III_(G) 3₄ Ejecting III_(G) first 107 III_(G)3₄ Ejecting III_(G) later 108 III_(G) 3₅ Ejecting III_(G) first 109III_(G) 3₅ Ejecting III_(G) later

[0329] The resultant recorded images were evaluated in accordance withthe methods described above. The results are shown collectively in Table7.

COMPARATIVE EXAMPLES 7 TO 11

[0330] Printing test and evaluation were performed in exactly the samemanner as in Examples 1 to 42 except that Inks 3₁ to 3₅ were separatelyused, but no liquid composition was used. The results are shown in Table8. TABLE 7 Image Fixing Quality of Resistance Water Ex. density abilitycharacter to bleeding fastness 64 AA AA AA AA AA 65 AA AA A AA AA 66 AAAA AA AA AA 67 AA AA AA AA AA 68 AA AA AA AA AA 69 AA AA A AA AA 70 AAAA AA AA AA 71 AA AA AA AA AA 72 AA AA AA AA AA 73 AA AA A AA AA 74 AAAA AA AA AA 75 AA AA AA AA AA 76 AA AA AA AA AA 77 AA AA AA AA AA 78 AAAA A AA AA 79 AA AA AA AA AA 80 AA A AA AA AA 81 AA A A AA AA 82 AA A AAAA AA 83 AA A AA AA AA 84 AA AA AA AA AA 85 AA AA A AA AA 86 AA A AA AAAA 87 AA A AA AA AA 88 AA AA AA AA AA 89 AA AA AA AA AA 90 AA A AA AA AA91 AA A A AA AA 92 AA A AA AA AA 93 AA A AA AA AA 94 AA AA A AA AA 95 AAAA AA AA AA 96 AA A AA AA AA 97 AA A AA AA AA 98 AA AA AA AA AA 99 AA AAAA AA AA 100  AA A AA AA AA 101  AA A A AA AA 102  AA A AA AA AA 103  AAA AA AA AA 104  AA AA AA AA AA 105  AA AA A AA AA 106  AA A AA AA AA107  AA A AA AA AA 108  AA AA AA AA AA 109  AA AA AA AA AA

[0331] TABLE 8 Comp. Image Fixing Quality of Resistance Water Ex.density ability character to bleeding fastness 7 AA B AA C C 8 AA B AA CC 9 B AA C C C 10 C C AA C AA 11 C C AA C AA

[0332] As has been described above, the practice of the presentinvention permits the provision of images satisfying high-speed fixing,high print quality, resistance to bleeding and perfect water fastnesseven when conducting color ink-jet recording on plain paper.

[0333] While the present invention has been described with respect towhat is presently considered to be the preferred embodiments, it is tobe understood that the invention is not limited to the disclosedembodiments. To the contrary, the invention is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims. The scope of the following claims is to beaccorded to the broadest interpretation so as to encompass all suchmodifications and equivalent structures and functions.

What is claimed is:
 1. A liquid composition comprising a cationicsubstance, wherein the liquid composition contains in combination acationic substance and a nonionic polymeric substance.
 2. A liquidcomposition comprising a cationic substance, wherein the liquidcomposition contains in combination a cationic oligomer having amolecular weight distribution in which a peak exists in a molecularweight region, and a nonionic polymeric substance.
 3. The liquidcomposition according to claim 1, wherein the cationic substance has amolecular weight of at most 1,000 and the nonionic polymeric substancehas a molecular weight of at least 2,000.
 4. The liquid compositionaccording to claim 2, wherein the peak in the molecular weightdistribution exists in a molecular weight region of not higher than1,000, and the nonionic polymeric substance has a molecular weight of atleast 2,000.
 5. The liquid composition according to claim 1, wherein thecationic substance and the nonionic polymeric substance are contained ina range of from 0.05 to 20% by weight in total.
 6. The liquidcomposition according to claim 2, wherein the cationic oligomer and thenonionic polymeric substance are contained in a range of from 0.05 to20% by weight in total.
 7. The liquid composition according to claim 1,wherein the cationic substance is a surfactant.
 8. The liquidcomposition according to claim 2, further comprising a cationicsurfactant.
 9. The liquid composition according to claim 1, wherein themixing ratio of the cationic substance to the nonionic polymericsubstance is within a range of from 10:1 to 1:10.
 10. The liquidcomposition according to claim 2, wherein the mixing ratio of thecationic oligomer to the nonionic polymeric substance is within a rangeof from 10:1 to 1:10.
 11. A liquid composition comprising a cationicsubstance, wherein the cationic substance has a molecular weightdistribution in which at least one peak exists in two molecular weightregions.
 12. The liquid composition according to claim 11, wherein atleast one peak exists in two molecular weight distribution regions ofnot higher than 1,000 and of not lower than 1,500 when measured by meansof GPC.
 13. The liquid composition according to claim 11, wherein thecationic substance is contained in a range of from 0.05 to 20% byweight.
 14. The liquid composition according to claim 11, wherein thecationic substance is composed of at least two compounds.
 15. The liquidcomposition according to claim 11, wherein at least one of the cationicsubstance is a surfactant.
 16. The liquid composition according to claim12, wherein the mixing ratio of the cationic substance having amolecular weight distribution in which at least one peak exists in twomolecular weight regions of not higher than 1,000 to the cationicpolymeric substance in which at least one peak exits in the molecularweight region of not lower than 1,500 is within a range of from 10:1 to1:10.
 17. An ink set comprising in combination the liquid compositionaccording to any one of claims 1 to 16 and at least one of yellow,magenta, cyan, black, red, blue and green inks.
 18. An ink setcomprising in combination the liquid composition according to any one ofclaims 1 to 16 and three inks of yellow, magenta and cyan colors.
 19. Anink set comprising in combination the liquid composition according toany one of claims 1 to 16 and four inks of yellow, magenta, cyan andblack colors.
 20. The ink set according to claim 17, wherein the inkscontain further an anionic compound.
 21. The ink set according to claim18, wherein the inks contain further an anionic compound.
 22. The inkset according to claim 19, wherein the inks contain further an anioniccompound.
 23. The ink set according to claim 17, wherein the inkscontain further a water-soluble dye having an anionic group.
 24. The inkset according to claim 18, wherein the inks contain further awater-soluble dye having an anionic group.
 25. The ink set according toclaim 19, wherein the inks contain further a water-soluble dye having ananionic group.
 26. The ink set according to claim 17, wherein the inkscontain further a pigment and an anionic compound.
 27. The ink setaccording to claim 18, wherein the inks contain further a pigment and ananionic compound.
 28. The ink set cording to claim 19, wherein the inkscontain further a pigment and an anionic compound.
 29. The ink setaccording to claim 20, wherein the anionic compound is a polymericsubstance having a molecular weight of at least 1,000.
 30. The ink setaccording to claim 21, wherein the anionic compound is a polymericsubstance having a molecular weight of at least 1,000.
 31. The ink setaccording to claim 22, wherein the anionic compound is a polymericsubstance having a molecular weight of at least 1,000.
 32. The ink setaccording to claim 20, wherein the anionic compound is a surfactant. 33.The ink set according to claim 21, wherein the anionic compound is asurfactant.
 34. The ink set according to claim 22, wherein the anioniccompound is surfactant.
 35. A process of forming an image, whichcomprises the steps of (A) applying the liquid composition according toany one of claims 1 to 16 to at least an image-forming region of arecording medium and (B) applying an ink comprising an anionic compoundto the recording medium by an ink-jet system.
 36. The image-formingprocess according to claim 35, wherein the ink-jet system is anOn-Demand type ink-jet system.
 37. The image-forming process accordingto claim 35, wherein the liquid composition is applied to the recordingmedium by an ink-jet system.
 38. The image-forming process according toclaim 35, wherein the ink-jet system is an ink-jet system in whichthermal energy is applied to the ink.
 39. The image-forming processaccording to claim 36, wherein the ink-jet system is an ink-jet systemin which thermal energy is applied to the ink.
 40. The image-formingprocess according to claim 37, wherein the ink-jet system is an ink-jetsystem in which thermal energy is applied to the ink.
 41. Theimage-forming process a cording to claim 35, wherein the step (A) isconducted prior to the step (B).
 42. The image-forming process accordingto claim 35, wherein the step (A) is conducted subsequently to the step(B).
 43. An image forming apparatus comprising the ink set according toclaim 17 and an ink-jet means.
 44. An image forming apparatus comprisingthe ink set according to claim 18 and an ink-jet means.
 45. An imageforming apparatus comprising the ink set according to claim 19 and anink-jet means.
 46. An image forming apparatus comprising the ink setaccording to claim 20 and an ink-jet means.
 47. An image formingapparatus comprising the ink set according to claim 21 and an ink-jetmeans.
 48. An image forming apparatus comprising the ink set accordingto claim 22 and an ink-jet means.
 49. An image forming apparatuscomprising the ink set according to claim 23 and an ink-jet means. 50.An image forming apparatus comprising the ink set according to claim 24and an ink-jet means.
 51. An image forming apparatus comprising the inkset according to claim 25 an ink-jet means.
 52. An image formingapparatus comprising the ink set according to claim and an ink-jetmeans.
 53. An image forming apparatus comprising the ink set accordingto claim 27 and an ink-jet means.
 54. An image forming apparatuscomprising the ink set according to claim 28 and an ink-jet means. 55.An image forming apparatus comprising the ink set according to claim 29and an ink-jet means.
 56. An image forming apparatus comprising the inkset according to claim 30 and an ink-jet means.
 57. An image formingapparatus comprising the ink set according to claim 31 and an ink-jetmeans.
 58. An image forming apparatus comprising the ink set accordingto claim 32 and an ink-jet means.
 59. An image forming apparatuscomprising the ink set according to claim 33 and an ink-jet means. 60.An image forming apparatus comprising the ink set according to claim 34and an ink-jet means.
 61. An image forming apparatus comprising thefirst recording unit equipped with a container part containing theliquid composition according to any one of claims 1 to 16 and anejection means therefor, and the second recording unit equipped withcontainer parts separately containing inks comprising an anioniccompound and ejection means therefor.
 62. The image forming apparatusaccording to claim 61, wherein the ejection means is an ink-jet means.63. The image forming apparatus according to claim 43, wherein theink-jet means is a means in which thermal energy is applied to the inkto form droplets of the ink.
 64. The image forming apparatus accordingto claim 44, wherein the ink-jet mean is a means in which thermal energyis applied to the ink to form droplets of the ink.
 65. The image formingapparatus according to claim 45, wherein the ink-jet means is a means inwhich thermal energy is applied to the ink to form droplets of the ink.66. The image forming apparatus according to claim 46, wherein theink-jet means is a means in which thermal energy is applied to the inkto form droplets of the ink.
 67. The image forming apparatus accordingto claim 47, wherein the ink-jet means is a means in which thermalenergy is applied to the ink to form droplets of the ink.
 68. The imageforming apparatus according to claim 48, wherein the ink-jet means is ameans in which thermal energy is applied to the to form droplets of theink.
 69. The image forming apparatus according to claim 49, wherein theink-jet means is a means in which thermal energy is applied the to formdroplets of the ink.
 70. The image forming apparatus according to claim50, wherein the ink-jet mans is a means in which thermal energy isapplied the ink to form droplets of the ink.
 71. The image formingapparatus according to claim 51, wherein the ink-jet means is a means inwhich thermal energy is applied to the ink to form droplets of the ink.72. The image forming apparatus according to claim 52, wherein theink-jet means is a means in which thermal energy is applied to the inkto form droplets of the ink.
 73. The image forming apparatus accordingto claim 53, wherein the ink-jet means is a means in which thermalenergy is applied to the ink to form droplet of the ink.
 74. The imageforming apparatus according to claim 54, wherein the ink-jet means is amean in which thermal energy is applied to the ink to form droplets ofthe ink.
 75. The image forming apparatus according to claim 55, whereinthe ink-jet means is a means in which thermal energy is applied to theink to form droplets of the ink.
 76. The image forming apparatusaccording to claim 56, wherein the ink-jet means is a means in whichthermal energy is applied to the ink form droplets of the ink.
 77. Theimage forming apparatus according to claim 57, wherein the ink-jet meansis a means in which thermal energy is applied to the ink to formdroplets of the ink.
 78. The image forming apparatus according to claim58, wherein the ink-jet means is a means in which thermal energy isapplied to the ink to form droplets of the ink.